3000 4000 principii de operare
TRANSCRIPT
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FOREWORD
This manual presents the Principles of Operation of the Allison 4
th
Generation Electronic Controls for the 3000 a
4000 Product Families transmissions. Mechanical, hydraulic, and electrical systems are described in detail.
This manual will help you become familiar with the operation of these transmissions and serve as a useful tool taid in service, diagnosis, and repair of these transmissions.
PRINCIPLES
OF OPERATION
PO4016E
IMPORTANT SAFETY NOTICE
IT IS YOUR RESPONSIBILITY to be completely familiar with the warnings and cautions described in this ma
ual. These warnings and cautions advise against the use of specific service methods that can result in personal
injury, damage to the equipment, or cause the equipment to become unsafe. It is, however, important to understa
that these warnings and cautions are not exhaustive. Allison Transmission could not possibly know, evaluate, and
advise the service trade of all conceivable ways in which service might be done or of the possible hazardous con
f h C tl Alli T i i h t d t k h b d l ti A d
SAFETY INFORMATION
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TRADEMARK USE
The following trademarks are the property of the companies indicated:
Allison DOC diagnostic tool is a trademark of General Motors Corporation. DEXRON
is a registered trademark of General Motors Corporation.
NOTES:
This publication is revised periodically to include improvements, new models, special tools, and procedures.
A revision is indicated by letter suffix added to the publication number. Check with your Allison Transmission
service outlet for the currently applicable publication. Additional copies of this publication may be purchased
from authorized Allison transmission service outlets. Look in your telephone directory under the heading ofTransmissionsTruck, Tractor, etc.
Shift selector displays and button names are indicated by TEXT IN CAPITALS.
Shift lever positions are indicated by a single bold letter or number
N
, D
, 1
, 2
, 3
, etc.
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The following abbreviations and symbols may be used in this manual.
Abbreviations and Acronyms ABS Anti-lock Brake System
AC Alternating Current
AT Allison Transmission
Aux Auxiliary
C1.......C7 Clutch 1........Clutch 7
CIN Calibration Identification Number
CLC Closed Loop Control CMC Customer Modifiable Constant
CR Close Ratio
DIF Differential
EEPROM Electrically Erasable Programmable Read Only Memory
Hz Hertz
ID Internal diameter
ISO International Standard Organization
LED Light emitting diode
LU Lockup
N.L. Normally Low/Normally Closed
NNC Neutral No Clutch
N.H. Normally High/Normally Open
ABBREVIATIONS AND SYMBOLS
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TSPD Turbine Speed Pull Down
VBS Variable Bleed Solenoid VIM Vehicle Interface Module
VIW Vehicle Interface Wiring
VR Volume Ratio
WOT Wide Open Throttle
WR Wide Ratio
Abbreviations and Acronyms (Continued)
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This service literature provides fully illustrated instructions for operation, maintenance, service, overhaul, and pa
support for your transmission. To achieve maximum performance and service from the 4
th
Generation transmis-
sion, these publications may be ordered from:
SGI, Inc.
Attn: Allison Literature Fulfillment Desk
8350 Allison Avenue
Indianapolis, IN 46268
TOLL FREE: 888-666-5799
INTERNATIONAL: 317-471-4995
3000 And 4000 Product Families Service Literature
Publication Name Publication No.
Allison DOC For PCService Tool User Guide GN3433EN
*Mechanics Tips3000/4000 Allison 4
th
Generation Controls (except 3700 7-speed) MT4015EN
*Mechanics Tips (3700 SP Allison 4
th
Generation Controls) MT4108EN
*Operators Manual (Bus Series) OM3749EN*Operators Manual (Emergency Vehicle Series) OM3656EN
*Operators Manual (Highway Series) OM3750EN
*Operators Manual (Motorhome Series) OM3349EN
*Operators Manual (Pupil Transport/Shuttle Series) OM3751EN
*Operators Manual (Rugged Duty Series) OM3752EN
SERVICE LITERATURE
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NOTES
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Section One Page
GENERAL DESCRIPTION
Scope of the Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Allison Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Model Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Transmission Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Transmission Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Remote Oil Cooler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Integral Oil Cooler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Transmission Oil Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Vehicle Adaptation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Oil Fill Tube/Dipstick Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Power Takeoff (PTO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Section Two
TRANSMISSION MODULES
Modular Design (Foldouts 16) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Input Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Torque Converter Module 11
TABLE OF CONTENT
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Retarder Electronic Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Retarder Accumulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Retarder Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Transfer Gear Module (Dropbox) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Electro-Hydraulic Control Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Section Three
ELECTRONIC CONTROL SYSTEM
System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Common to all 3000 and 4000 Product Families Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Optional on Some 3000 and 4000 Product Families Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . 25
Used on all 3000 and 4000 Product Families Transmissions Retarder Units
(Except 7-Speed Models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Used on 3000 and 4000 Product Families 7-Speed Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Transmission Control Module (TCM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Variable Bleed Solenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Normally Low and Normally High VBS Solenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
ON/OFF Solenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
PWM Solenoids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
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Turbine Speed and Output Speed Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3000 Product Family Transmissions (Except 7-Speed Models) . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4000 Product Family Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3000 Product Family 7-Speed Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Vehicle Interface Wiring (VIW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Vehicle Communications Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
J1939 Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Typical Data Received. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Typical Data Transmitted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
J1708/J1587 Serial Communications Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
ISO 9141 Communication Link (A43 Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Special Input and Output Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Power Takeoff (PTO) Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Wiring Harnesses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
External Wiring Harness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Internal Wiring Harness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
TransID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
S i F
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Section Five
HYDRAULIC SYSTEM
System Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Hydraulic Schematic Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Transmission Hydraulic System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Main-Pressure Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Solenoids and Solenoid Regulator Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Main Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Clutch Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Hydraulic Operation During Electrical Interruption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Control Main Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Torque Converter Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Converter-In Pressure Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Low Converter-In Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Moderate Converter-In Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59High Converter-In Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Extremely High Converter-In Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Cooler/Lubrication Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Exhaust Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
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LIST OF FOLDOUT ILLUSTRATIONS
Hydraulic Schematics
H-1. 3000 and 4000 Product Families Hydraulic SchematicNeutral
H-2. 3000 and 4000 Product Families Hydraulic SchematicReverse
H-3. 3000 Product Family Hydraulic Schematic7-Speed, Low Range
H-4. 4000 Product Family Hydraulic Schematic7-Speed, Low Range
H-5. 3000 and 4000 Product Families Hydraulic SchematicFirst Range
H-6. 3000 and 4000 Product Families Hydraulic SchematicSecond Range
H-7. 3000 and 4000 Product Families Hydraulic SchematicThird Range
H-8. 3000 and 4000 Product Families Hydraulic SchematicFourth Range
H-9. 3000 and 4000 Product Families Hydraulic SchematicFifth Range
H-10. 3000 and 4000 Product Families Hydraulic SchematicSixth Range
H-11. 3000 Product Family Hydraulic SchematicRetarder OFF
H-12. 3000 Product Family Hydraulic SchematicRetarder ON
H-13. 4000 Product Family Hydraulic SchematicRetarder OFF
H-14. 4000 Product Family Hydraulic SchematicRetarder ON
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NOTES
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Section On
GENERAL DESCRIPTIO
SCOPE OF THE MANUAL
The principles of operation discussed in this manual
describe the components and operation of thefollowing Allison transmissions:
3000 Product Family transmissions
3000 HS
3000/3500 RDS
3000/3500 EVS
3000 MH 3000/3200 TRV
3000 PTS
3000/3200/3500 SP
3700 SP (7-speed Dropbox No Retarder)
B 300/400
T 200/300 4000 Product Family transmissions
4000/4500 HS
4000/4500 RDS
4700 RDS (7-speed)
Hydraulic Schematic H3 illustrates the low-
range of 3000 Product Family 7-speed models
Hydraulic Schematic H4 illustrates the low-range of 4000 Product Family 7-speed models
Hydraulic Schematics H5 through H10 illus
trates the first through sixth ranges of 3000 an
4000 Product Families transmissions.
Hydraulic Schematic H11 illustrates the
retarder OFF mode of 3000 Product Family
transmissions. Hydraulic Schematic H12 illustrates the
retarder ON mode of 3000 Product Family tra
missions.
Hydraulic Schematic H13 illustrates the
retarder OFF mode of 4000 Product Family
transmissions.
Hydraulic Schematic H14 illustrates theretarder ON mode of 4000 Product Family tra
missions.
Foldout 1 is a cross section of a typical 3000
Product Family transmission (except 7-speed)
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MODEL NOMENCLATURE
HS Highway Series
RDSRugged Duty Series
EVS Emergency Vehicle Series
MH Motorhome Series
3 0 0 0 HS
Code Explanation
VOCATIONAL MODELS
ALLISON TRANSMISSIONS
Allison transmissions are designed as complete, fully-
automatic transmission systems. Refer to Figures 1
through 6. Some models have capacity for six
forward speeds, neutral, and one reverse. Other
models with a transfer case or C6 adapter housing
provide seven forward speeds, neutral, and one
reverse. However, the electronic controls may be
custom programmed for four-speed or five-speed
operation to best meet some vocational requirements.
Allison transmissions contain hydraulically-actuated,spring-released clutches. Compensation for clutch
wear occurs automatically. Electronic controls, using
closed-loop logic, provide optimum driving efficiency
by shifting at the exact programmed transmission shift
points for every engine/transmission/vehicle vocation
combination.
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PTOPROVISION
OUTPUTSPEED
SENSOR
NAMEPLATE
RIGHT-REAR VIEW
INPUTSPEEDSENSOR
ASSEMBLY PADS
MAIN-PRESSURE TAPNOTE:Inch Series Threads
BREATHER
FEEDTHROUGH HARNESSCONNECTOR
COOLER PORTSNOTE:Inch Series Threads
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ASSEMBLY PADS(BOTH SIDES)
OUTPUTTORQUE CONVERTER
WITH LOCKUP CLUTCH
BREATHER
RETARDERVALVE BODYCONNECTOR
OUTPUT
SPEEDSENSOR
ASSEMBLY PADS
MAIN-PRESSURE TAPNOTE:Inch Series Threads
BREATHER
COOLER PORTSNOTE:Inch Series Threads
LEFT-REAR VIEW
TACHOGRAPH PROVISIONNOTE: Metric Series Threads
SUMPCOOLERPROVISION
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Worldrld
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RIGHT FRONT-VIEW
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TURBINE SPEEDSENSOR
MOUNTINGPAD
SHIPPINGBRACKET (3)
ENGINE SPEEDSENSOR
NAMEPLATE
FILL TUBEOUTPUT SPEED
SENSOR
FEEDTHROUGHHARNESS
CONNECTOR
PTO(TOP RIGHT POSITION)
COOLER PORTS
MOUNTING PAD
RIGHT-REAR VIEW
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RIGHT-FRONT VIEW
PTO (TOP RIGHT POSITION)
PTO (TOP RIGHT POSITION)
MOUNTING PADS(BOTH SIDES)
MOUNTING PADS(BOTH SIDES)
FILL TUBETURBINE
SPEEDSENSOR
ENGINE SPEED SENSOR
NAMEPLATE
FEEDTHROUGHHARNESS
CONNECTOR
RETARDER
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(LEFT-REAR VIEW)
C6 ADAPTERHOUSING
REAR COVER
PTO (TOP RIGHT POSITION)
MOUNTING PADS(BOTH SIDES)
MOUNTING PADS(BOTH SIDES)
PTO (BOTTOM LEFTPOSITION)
MAIN-PRESSURE TAP
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TRANSMISSION IDENTIFICATION
The transmission identification plate (nameplate) is
located on the right-rear side of the transmission (referto Figures 1, 4, and 5). The nameplate (refer to
Figure 7) shows the transmission serial number, part
number (assembly number), and model number. Use
all identification numbers when ordering parts.
Figure 7. Transmission Identification Plate (Nameplate)
GeneralMotors Corp.
Indianapolis, Indiana, USA
S/N XXXXXXXXXX
TIDA
00A00
ECA
PS
O R E
A,
EL
IBOMOTUADETI NUAC
IREMA
FOSRE KR
O
WT
N E
MEL
PMILA
RUTLUCIRGADN
A
ENGINEERING FEATURECONFIGURATION NUMBER FIELD
MODEL NUMBER FIELD
V09468.00.00
Water lines are needed to route engine-cooling water
and from the cooler.
Cooler types and configurations are selected by theoriginal equipment manufacturer (OEM).
TRANSMISSION OIL FILTERS
Two cartridge-type transmission fluid filters (refer to
Figure 8) service the main fluid supply and cooler
circuit. These filters are enclosed within the
transmission control module. Filter access is throughcover plates in the bottom of the control module. Wh
the filters are removed, the only transmission fluid lo
is the fluid in the filter cavities.
VEHICLE ADAPTATION
An Allison transmission may be used with most maj
diesel engines. Adaptation parts adapt the transmissi
to a Society of Automotive Engineers (SAE) No. 1 o
No. 2 engine flywheel housing and/or flexplate adapt
These adaptation parts include the following:
Flexplates
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FILTERCOVER
DRAINPLUG
DRAINPLUG
V03532.04.00
4000 PRODUCT FAMILY 3000 PRODUCT FAMILY
MAINMAINLUBE LUBE
6
5
4
2
1
3
MAINLUBE
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MODULAR DESIGN
(Foldouts 16)
The 3000 and 4000 Product Families transmissions arecomposed of major assemblies called modules. Each
module may be removed and serviced as a separate
unit. The modular design of the transmission assures
proper assembly and simplifies servicing of the
transmission. The following modules, together with the
external portion of the electronic control system and
support equipment, comprise the total transmission
system.
INPUT MODULES:
Torque converter module
Converter housing module
Front support/charging pump module
GEARBOX MODULES:
Rotating clutch module Main housing module
P1 planetary module
P2 planetary module
P3 planetary module
INPUT MODULES
Input modules are required to connect the transmissi
to an engine. An input module is located between theengine and the transmission gearbox modules.
TORQUE CONVERTER MODULE
The torque converter operates hydraulically and
transfers torque from the engine to the transmission.
consists of a:
Vaned converter pump. Vaned turbine.
Vaned stator.
Lockup clutch and torsional damper assembly
Refer to Section 6, Torque Paths, for a detailed
description of torque converter and lockup operation
CONVERTER HOUSING MODULE
The converter housing module connects the engine a
the gearbox modules.
Provision(s) to mount power takeoff (PTO) units are
the converter housing (refer to Figures 1 4 5 and 6;
Section TwTRANSMISSION MODULE
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GEARBOX MODULES
The basic gearbox modules contain five clutch
assemblies and three planetary gear sets to provide sixforward speeds, neutral, and one reverse.
The 4000 Product Family 7-speed transmissions
contain six clutch assemblies and four planetary gear
sets to provide seven forward speeds, neutral, and
reverse.
Transmissions with six forward ranges contain two
overdrive ranges, fifth-range, and sixth-range.
Transmissions with seven forward ranges contain a
low-range and two overdrive ranges, fifth-range, and
sixth-range.
The following transmissions are available with wide
ratio gearing:
4500 HS 3500 RDS 3500 SP
3500 EVS 4500 RDS 3700 SP
4500 EVS 4700 RDS 4500 SP
4700 EVS 4700 SP
4800 EVS 4800 SP
The functional components of the C1 and C2 clutches
are:
Pistons. Return spring assemblies.
Clutch reaction plates.
Clutch friction plates.
Drive hub.
The C1 clutch reaction plates are splined to and rotate
with the rotating clutch hub assembly. The C1 clutch is
applied by charged hydraulic fluid pressing the C1clutch piston, return spring assembly, and clutch
reaction plates against the clutch friction plates. This
action causes the C1 drive hub, which is splined to the
clutch friction plates, to rotate, delivering torque to the
main shaft assembly.
The C2 clutch reaction plates are splined to and rotate
with the rotating clutch drum. The C2 clutch friction
plates are splined to the C2 drive hub. Chargedhydraulic fluid presses the C2 piston, spring assembly,
and reaction plates against the clutch friction plates.
This action causes the C2 drive hub, which is splined to
the C2 clutch friction plates, to rotate, transmitting
torque to the P2 planetary assembly
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applied. The Transmission Control Module (TCM)
signals solenoid valves in the control module to apply
and release clutches based on speed and power
requirements.
P1, P2, or P3 planetary ring gears are held stationary by
stationary clutches C3, C4, or C5 respectively, when
the clutches are applied.
C3 and C4 clutches in the main housing module are
assembled as a unit. These clutches consist of:
Piston.
Piston return plate assembly.
Clutch plates.
The P1 ring gear is also enclosed in the C3 clutch
assembly.
The C5 friction and reaction plates are components of
the C5 clutch contained in the main housing. The C5
piston and spring assembly are assembled as a part ofthe rear cover module, retarder module, or transfer gear
adapter housing.
The C3 clutch friction plates mesh with the P1 ring
gear. The friction plates rotate with the P1 carrier
P1 PLANETARY GEAR MODULE
P1 is the first planetary gear set assembly. P1 consists
Sun gear, driven by the rotating clutch drum. P1 carrier assembly, containing the P1 pinion
gears.
P1 ring gear, housed in the C3 clutch assembly
The P1 carrier is meshed with the P1 ring gear insid
the C3/C4 clutch assembly. The P1 sun gear is insert
into the center of the P1 carrier assembly where it
meshes with the P1 pinion gears. The ring gear of th
P2 planetary gear set is splined to the P1 carrier and
meshes with the C4 clutch friction plates.
The rotation of P1 planetary gears is controlled by th
application of either the C3 or C4 clutch assembly.
Input to P1 planetary is provided through the P1 sun
gear meshing with the P1 carrier.
P2 PLANETARY GEAR MODULEP2 is the second planetary gear set assembly. P2
consists of:
Sun gear, splined to the main shaft.
P2 carrier assembly, containing the P2 pinion
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The P3 sun gear meshes with the P3 pinion gears,
rotating on the inside of the P3 carrier assembly. The
transmission output shaft is splined to, and rotates with,
the P3 carrier assembly.
MAIN SHAFT MODULE
The main shaft module passes through the center of the
transmission gearbox. The P2 and P3 sun gears are part
of or splined to the main shaft, enabling it to transmit
torque to the P2 and P3 planetary assemblies. The main
shaft is splined to the rotating clutch module. Inputtorque to the main shaft is received either through the
rotating clutch module output or the P2 carrier. The
main shaft provides the primary path for transmitting
torque through the various stages of the transmission.
The 3700 SP uses a special main shaft that extends
through the P3 sun gear to the C6 clutch in the transfer
gear housing.
C6 ADAPTER HOUSING MODULE(4000 Product Family 7-Speed Models)
The C6 adapter housing module is unique to the 4000
Product Family 7 speed models It provides a seventh
The output centerline of the straight-through 6-speed
and 7-speed transmissions is in line with the
transmission input centerline. The transmission output
may be equipped with the following:
Rear cover module
Transfer gear housing module
Output retarder module
Parking brake provision
Remote or integral cooler provision
3700 SP (7-speed) has a dropbox output A variety of yokes and flanges to best adapt the
transmission to its particular application
REAR COVER MODULE3000 and 4000 Product Families(Except 7-Speed Models)
This module houses the following:
P3 carrier component of the P3 planetary gear set
Output shaft assembly
C5 clutch piston
S d bl
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OUTPUT RETARDER MODULE (NotAvailable on 3000 Product Family 7-SpeedTransmissions)
The output retarder module (except 4000 Product
Family 7-speed models) includes the following:
P3 carrier of the P3 planetary gear set
Output shaft assembly
C5 clutch piston
Output speed sensor assembly
Output flangeThe output retarder module for 4000 Product Family
7-speed models houses the following:
Output shaft assembly
C6 clutch piston
WARNING:
DO NOT USE THE RETARDER DURING
INCLEMENT WEATHER OR WHEN ROAD SUR-
FACES ARE SLIPPERY. Loss of vehicle control
may cause injury or property damage. De-energize
the retarder at the retarder enable switch.
released upon retarder activation to assist in charging
the retarder cavity. The retarder housing is evacuated
fluid (and the accumulator is charged) when the
retarder is not in use.
VANED STATOR HOUSING
VANED ROTOR
VANEDRETARDERHOUSING
OUTPUTSHAFT
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VANED ROTORVANEDSTATOR
HOUSING
VANEDRETARDERHOUSING
OUTPUT
SHAFT
RETARDER CAPACITIES
3000 and 4000 Product Families retarders are available
in three different capacities: Low, Medium, and High.
Maximum retarder capacity is determined by the TCM
calibration in Allison 4th Generation Controls systems.
3000 Product Family retarders are capable of absorbing
the following torque and horsepower:
4000 Product Family retarders are capable of absorbing
the following torque and horsepower output:
Capacity Power Torque
Low298 kw
(400 hp)1491 Nm
(1100 lb ft)
Medium373 kw
(500 hp)1763 Nm
(1300 lb ft)
High447 kw
(600 hp)2169 Nm
(1600 lb ft)
Capacity Power Torque
Low373 kw
(500 hp)1763 Nm
(1300 lb ft)
Medium447 kw 2169 Nm
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NOTE:
With Allison 4th Generation Controls, the retarder
accumulator solenoid will remain OFF when RMR
device retarder request percentage is less than
20 percent. Additionally, the retarder accumulator
solenoid will not activate when torque request is
less than 343 Nm (253 lb ft) for 3000 Product Fam-
ily retarder transmissions and 374 Nm (276 lb ft)
for the 4000 Product Family retarder transmis-
sions. This is intended to enhance retarder regula-
tor valve and relay valve operation at low retarder
request percentages.
Operator control of the retarder can be accomplished
by either of the following two methods. The TCM must
be calibrated to the proper method to be sure of desired
retarder operation:
Both Analog and J1939
Analog activation is based on a Retarder
Enable switch, coupled with one or moreAllison Retarder Modulation Request (RMR)
components to select the desired level of
retardation.
Retardation is requested on a limited basis on
a message from an SAE J1939-based vehicle
limited by TSC1 torque limit messages sent by certa
devices on the vehicle network, such as ABS. Refer
Allison Transmission publication TS3989EN,
Troubleshooting Manual, Appendix R, for the ERC1and TSC1 messages.
A master control is required, which permits the
operator to enable or disable the retarder system
regardless of the source of retarder activation.
J1939 Only
This calibration option should be selected when ther
will be no analog inputs from the RMR devices. Inpuis based on messages from an SAE J1939-based
vehicle controller in the form of a single ERC1
Retarder Selection, Non-Engine parameter, or by on
or more TSC1 torque control messages. Retarder
operation may also be limited by TSC1 torque limit
messages sent by certain devices on the vehicle
network, such as ABS. Refer to Allison Transmission
publication TS3989EN, Troubleshooting Manual,
Appendix R, for the ERC1 and TSC1 messages.
A master control is required, which permits the
operator to enable or disable the retarder system
regardless of the source of retarder activation.
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An in-depth discussion of the types and combinations of
controls, their respective applications, and installation
recommendations are discussed in Allison Transmission
Technical Document No. 175, Guidelines for Selectionof Allison 4th Generation Retarder Controls. A brief
description of each analog device follows.
Hand LeverThe operator selects OFF or one of six
levels of retardation. Each successive level sends a
higher voltage to the TCM and the TCM signals the
retarder to supply a corresponding amount of
retardation. Higher voltage to the TCM produces
increased retardation with maximum retardation inposition six.
Separate Foot Pedal (No Service Brake Apply)
The operator selects the amount of retardation by pedal
position (zero to 100 percent). Maximum retardation is
obtained at full pedal stroke. A voltage that is
proportional to pedal movement is sent to the TCM.
The TCM signals the retarder to supply a
corresponding amount of retardation. Foot pedals are
available with different amounts of angular movement
to fit OEM or body builder requirements.
Pressure SwitchThis option integrates retarder
activation with the vehicle service brake system One to
when certain conditions are met (typical percent
applies are 33 and 50).
CombinationAlmost any two of the retarder apply
systems described above can be used together in the
same vehicle. A combination of controls allows greater
flexibility in applying the retarder. Some typical
combinations used are:
Hand lever and single pressure switchsix lev-
els of modulation or 100 percent apply with ser-
vice brake pressure.
Hand lever and 3-step pressure switchsix lev-els of modulation or three levels of modulation
based on service brake apply pressure.
Auto apply (auto 50 percent on) and single pres-
sure switch50 percent retarder at certain con-
ditions or 100 percent apply with service brake
pressure.
Auto apply (auto 33 percent on) and two pressure
switches33 percent retarder at certain condi-tions or 67 percent or 100 percent apply with ser-
vice brake pressure.
RETARDER ELECTRONIC CONTROLS
The electronic retarder controls consist of:
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are normally closed (must be electrically energized to
perform their function).
The retarder temperature sensor sends retarder
temperature information to the TCM. The TCM uses
this data to:
Turn on a dash light to alert the operator when an
over-temp condition is present.
Log diagnostic codes.
Reduce retarder capacity in over-temp situations.
Invoke a preselected downshift.
Control retarder torque to requested level.
Some input functions and output functions are required
with retarder equipped transmissions. Input functions
send a signal to the TCM. Output functions are control
signals sent from the TCM. The input and output
functions used in conjunction with the retarder are:
Retarder EnableA signal sent to the TCM to
Input Function Output Functions
Retarder Enable
Service Brake Status
Anti-Lock Brake Response
Retarder Indicator
Retarder Temperature
Indicator
The ABS response may come to the TCM via a J193
message. In this case, the discrete input is not requir
Retarder IndicatorThis signal from the TCMactivates the vehicle brake lights when the retarder is
applied and may also illuminate an optional retarder
indicator light.
Retarder Temperature IndicatorThis signal from
the TCM activates an indicator light when retarder
temperature has exceeded a calibration limit.
Retarder/Cruise Control Interactions
Two control features affect how the retarder operates
when the vehicle is equipped with cruise control:
Feature 1: Cruise Control Retarder Auto On Disabl
This feature applies only to electronic engines that
communicate with the transmission on either J1587
J1939. The TCM calibration must specify this featur
to be either ON or OFF.
If the feature is ON in the calibration, the TCM
prohibits retarder operation when cruise is active but
the throttle is closed, which implies a downhill coasti
operation. This feature is highly recommended if the
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Configuration A. If the retarder is activated by the
brake pedal with no auto apply:
Neither Feature 1 nor Feature 2 is required.Configuration B. If the retarder is activated by the
brake pedal with auto apply:
Feature 1 keeps the retarder OFF during cruise
operation when the engine percent load goes to
zero. Feature 2 would have no effect because
depressing the brake pedal will turn off cruise
anyway. Therefore, it doesnt matter if Feature 2
is turned ON or OFF.
Configuration C.If the retarder is activated by a lever,
it will auto apply at the appropriate level according to
the lever position when throttle reaches zero percent.
Using Feature 1 and Feature 2Feature 1 will
keep the retarder OFF during cruise operation
when the engine percent load goes to zero. If
Feature 1 has already prevented the auto apply
and the engine percent load is still at zero, Fea-
ture 2 will cause the retarder to come on and dis-
able cruise if the lever is moved to increase
retarder capacity above a calibrated rate during a
RETARDER ACCUMULATOR(Refer to Figures H11 Through H14)
NOTE:The terms left, right, up, and down are directions
on the figures and hydraulic schematics referenced
by this description of retarder operation.
The accumulator is a remotely mounted, sealed,
cylindrical container that contains a reserve quantity of
transmission fluid for initial fill of the retarder. The
accumulator is connected to the retarder by a Size 20
hose. Also connected to the accumulator is the
vehicles air system through an air regulator/pressure
protection valve.
Transmission fluid stored in the accumulator is
discharged into the retarder by a piston located in the
accumulator. This piston is forced toward the right-side
of the accumulator by air pressure only. Once the
retarder is deactivated, air pressure is exhausted on theleft-side of the piston and retarder pressure pushes the
piston back to the left side of the accumulator. This
recharges the accumulator until the next retarder
application. After the retarder flow valve shifts,
converter out pressure is aligned to the cooler circuit
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cooler circuit. The converter flow circuit is
aligned to an auxiliary sump cooler in the vehi-
cle, if so equipped.
When SS2 is energized, vehicle air pressure
strokes the retarder accumulator piston to the
right. Oil stored in the accumulator discharges
into the retarder housing, which initiates vehicle
retardation.
The initial charge of fluid is continuously supple-
mented by retarder charge pressure from the
retarder regulator valve. The TCM varies currentto PCS5 to achieve the desired retarder output
torque based on calibrated capacity, request per-
centage, and output speed.
The orifice located in the circuit at the bottom
of the regulator valve bore damps pressure fluc-
tuations within the retarder hydraulic circuit pro-
viding a stable retarder charging pressure.
The orifice located in the circuit at the bottom
of the relay valve bore limits retarder charge
pressure in the event of a stuck open retarder
regulator valve. If the regulator valve sticks open,
charge pressure would increase and approach
Main pressure is exhausted from the right side
large retarder flow valve. The flow valve move
right due to spring force acting on the left side
the valve. This opens an exhaust path that evacates the retarder cavity.
Converter out fluid is redirected to the main
transmission oil cooler and lube circuit. Con-
verter out pressure keeps the accumulator
charged.
The 4000 Product Family retarders contain one
additional valvean exhaust check valve. The functiof the exhaust check valve is to prevent drawing flui
from the sump into the retarder cavity when the
retarder is in the OFF mode. This is specific only to
4000 Product Family transmissions due to the diamet
of the retarder housing and the placement of the
retarder valve body.
TRANSFER GEAR MODULE(DROPBOX) (Figure 3, Foldout 3)
The 3000 Product Family 7-speed transmission (also
called the Drop-7) uses a transfer gear module
consisting of the following:
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The addition of the transfer gear module provides the
vehicle with the following:
Seven forward ranges
Neutral
Reverse
Full-time, all-wheel drive capability
The C6 clutch is engaged to provide a first-range with a
deeper gear ratio than the first-range of the straight-
through transmission.
The output adapter housing contains the C5 clutch
piston and provides a mounting face for the transfer
case.
The transfer case is mounted to the adapter housing and
extends below the transmission. A transmission output
shaft adapter is splined to the P3 carrier hub. The
transfer case charging pump and the transfer case drive
gear, installed between the P3 carrier and the C6 clutch
assembly, are mounted on and driven by the output
shaft adapter. The drive gear directs torque into the
transfer case. When engaged, the stationary C6 clutch
holds the main shaft and provides first-range operation.
The transfer case idler gear is installed between the
transfer case drive gear and driven gear. The idler gear
transfers torque from the drive gear to the driven gear.
Therefore, the driven gear turns in the same direction
as the drive gear.
The transfer case driven gear meshes with the P4
planetary assembly which drives the front and rear
output shafts. When the C7 differential clutch is
engaged (in difficult traction situations), the outputs are
locked. When the C7 clutch is not engaged, there is a
30/70 split in driving torque (30 percent to the front
driveline).
The transmission hydraulic system provides the
pressure to apply the C6 and C7 clutches and to
lubricate the transfer case components. The scavenge
pump mounted on the right-hand PTO pad returns
transmission fluid from the transfer case back into themain housing to supplement lube pressure. The oil
pump in the transfer case provides lube to the transfer
case components when the vehicle is being towed with
the wheels on the ground.
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ELECTRO-HYDRAULIC
CONTROL MODULE
The control module (Figure11) houses the solenoids,sensors, valves, and regulators that control the pressure
and flow of transmission fluid to the clutches, the
torque converter, and the lubrication/cooling hydrau
circuits (refer to Section 5). The control module also
houses the transmission fluid filters. The channel plaprovides the bottom enclosure for the transmission.
6-SPEED3000 PRODUCT FAMILY
CONTROL MODULE
7-SPEED3000 PRODUCT FAMILY
CONTROL MODULE
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NOTES
Section Thre
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SYSTEM COMPONENTS
The electronic control system for Allison 4th
Generation Controls consists of the followingcomponents.
COMMON TO ALL 3000 AND 4000 PRODUCTFAMILIES TRANSMISSIONS
Transmission Control Module (TCM)
Pressure control solenoids PCS1PCS4
Lockup clutch solenoid TCC
Forward latch solenoid SS1
Shift selector(s)
Engine speed sensor
Turbine speed sensor
Output speed sensor
PS1 pressure switch
Sump temperature sensor
OPTIONAL ON SOME 3000 AND 4000PRODUCT FAMILIES TRANSMISSIONS
Oil level sensor (OLS)
Special input and output functions
Power Takeoff (PTO) functions
Serial Communication Interface (J1587 and
J1939)
Vehicle interface module (VIM)
Throttle position sensor (TPS)
Vehicle Interface Wiring (VIW)
USED ON ALL 3000 AND 4000 PRODUCT FAMLIES TRANSMISSIONS RETARDER UNITS(EXCEPT 7-SPEED MODELS)
Retarder temperature sensor
Control valve solenoid PCS5
Accumulator solenoid SS2
Resistance modules
External controls (pedal, lever, etc.)
USED ON 3000 AND 4000 PRODUCT FAMILIE7-SPEED MODELS
C6 clutch solenoid PCS6
ELECTRONIC CONTROL SYSTEM
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TRANSMISSION CONTROL
MODULE (TCM)
The TCM (refer to Figure 12) is a microcomputer thatis available in the following three models:
Model A41the basic configuration used by
6-speed 3000 and 4000 Product Families trans-
mission in a 12V electrical system.
Model A42the expanded configuration used by
retarder-equipped or 7-speed 3000 and 4000
Product Families transmission with a 12V elec-
trical system.
Model A43the universal configuration used by
24V applications.
The TCM is a microcomputer that receives and
processes signals from various switches and sensors.
TCMs are available in both 12V and 24V
configurations to match the configuration of the vehicle
electrical system.Input from the operator is sent to the TCM via the shift
selector and vehicle interface wiring. The TCM
determines:
Shift sequences
determine the characteristics of a shift in progress. The
TCM includes flash memory where program
information, calibration information, and optimum
shift calibration for a specific vocation are stored.
Calibration and program information can be changed
electronically. Actual transmission shift characteristics
are compared to the optimum shift calibration stored in
the TCM. If the reported shift characteristics are not
within programmed limits, the TCM alters solenoid
current commands to bring the shift within the limits.
The TCM produces excellent shift quality byconstantly adjusting for changes in operating
conditions, applying closed loop control, and using
adaptive logic.
The TCM constantly monitors operating conditions
such as battery voltage and transmission sump
temperature and adjusts shift parameters accordingly.
The closed loop control makes during shiftadjustments. These adjustments in shift characteristics
are based on vehicle conditions such as grade, load,
and engine power. After a shift is completed, the TCM
compares the shift to an ideal shift profile in the
TCM calibration and makes adjustments before the
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The TCM has an autodetect feature. Autodetect is
active within the first 30 seconds of the first 24 engine
starts or 49 engine starts, depending upon the
component or sensor being detected.
Autodetect searches for the presence of the following
transmission components or data inputs.
Even after autodetect has been completed, it can be
reset to monitor an additional group of engine starts.
Reset may be necessary if a device known to be present
is not detected or if an autodetectable component or
sensor was added after the initial vehicle build.
Reset is accomplished by using the Allison DOCdiagnostic tool. It also may be used to override
autodetect and manually enter the component or sensor
to be recognized by the TCM by changing the
appropriate customer modifiable constants (CMC).
C lt Alli bli ti GN3433EN Alli
Retarder Present, Not Present
Oil Level Sensor (OLS) Present, Not Present
Throttle Analog, J1587, J1939,
CAN
Engine Coolant Temperature Analog, J1939, J1587
During the first 24 engine starts, autodetect does not
retain what was detected on the previous engine star
For example, if a retarder was detected on engine
start 23, PCS5 diagnostics would be performed untilthe TCM was turned off. If PCS5 then failed after th
TCM was turned off, but prior to engine start 24,
autodetect would not know that a retarder was prese
on engine start 24 and no diagnostics would be
conducted for PCS5.
The TCM is programmed to protect the transmission
and other vehicle driveline components from abuse b
inhibiting actions such as full-throttle neutral-to-rangshifts and high-speed direction changes.
The TCM determines if a system malfunction exists
and stores diagnostic codes related to the malfunctio
The codes, accessed by the operator or service
mechanic, are used in diagnosing persistent or
intermittent trouble in the system (refer to Section 4)
VARIABLE BLEED SOLENOIDS(VBS)
NOTE:
Th t l ft i ht d d di ti
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VBS SOLENOID
(High Pressure State)
EXHAUST
PORTSUPPLY
CONTROL
PORT
SUPPLY ORIFICE
(Full Open) METERING ORIFICE
( Closed)V09512.00.00
at the control port. As the variable metering orifice is
opened (Figure 14), fluid flows to exhaust through the
fixed supply orifice resulting in a pressure drop across
the supply orifice and a lower pressure at the control
port. The larger the variable metering orifice, the more
fluid is bled to exhaust and the lower the pressure at the
control port.
Variable bleed solenoids are of a closed end design
meaning they have a shut-off feature that minimizes
fluid flow in the minimum pressure state. When the
metering orifice is full open (Figure 15), a ball closes
off the supply orifice. The fluid in the control port is
bled to exhaust resulting in minimum pressure at the
control port without fluid flow from the supply port.
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NORMALLY LOW AND NORMALLYHIGH VBS SOLENOIDS
There are two types of VBS used in the 3000 and 4000
Product Families transmissions, normally low (NL)
and normally high (NH).
ON/OFF SOLENOIDSOn/Off solenoids are designed to connect the contro
port of the solenoid to either supply pressure or
exhaust.
The On Off solenoids have two o rings and three po
Figure 15. Variable Bleed SolenoidLow Pressure State
VBS SOLENOID(Low Pressure State)
EXHAUST
PORTSUPPLY
CONTROL
PORT
SUPPLY ORIFICE
(Closed) METERING ORIFICE
(Full Open)V09514.00.00
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The PWM solenoid has two o-rings and three ports:
Supply port in the side of the solenoid snout
between the o-rings
Control port at the end of the snout
Exhaust port out the back of the solenoid
The PWM solenoid (refer to Figure 15) is normally low
(NL) which means the supply port is blocked and the
control port is connected to the exhaust port when de-
energized. When sufficient electrical current is supplied
to the solenoid, the supply port is connected to the
control port and the exhaust port is blocked.
During application of a clutch, the TCM turns the
solenoid ON and OFF at an established frequency,
typically between 60 and 100 times per second. The
longer the solenoid is left ON, the higher the effective
pressure at the clutch.
The 3000 Product Family 7-speed transmission uses a
PWM solenoid to control the differential lock clutch.
UPSHIFT CLUTCH CONTROL
The upper curve on the chart in Figure 16 representsbi d d i i l hif Th iddl
TCM commands an automatic range upshift to begin
(refer to Figure 16).
At shift initiation, the solenoid is commanded
fully ON for a period of time. This is called Vol-
ume Ratio (VR). This is done to start the piston
moving. The solenoid pressure command during
this period is a relative high flow. VR is an
important troubleshooting tool. A significant
change indicates a clutch apply problem that
requires attention.
At the end of VR, the oncoming clutch is at its
Initial Oncoming Pressure.
The solenoid is signaled by the TCM to increase
pressure to the oncoming clutch at the Open
Loop Ramp Rate (OLRR). The OLRR is a preset
rate of increase in clutch pressure that will con-
tinue until Turbine Speed Pull Down (TSPD) is
detected.
During VR and OLRR of the oncoming clutch,the off-going clutch-apply pressure is decreasing.
After TSPD is detected, the TCM enters Closed
Loop Control (CLC) of the oncoming clutch.
CLC is the period when the TCM is actively con-
t lli t bi d b dj ti th
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Figure 16. Automatic Clutch Application Control
ONCOMINGCLUTCH
PRESSURECOMMAND 0%
100%ON
100%ON
SYNCHRONOUSSPEED DETECTED(TURBINE SPEED =
OUTPUT SPEED x GEAR RATIO OF ONCOMING CLUTCH)
PULL DOWNDETECTED
TIMECLOSED LOOP
CONTROLPRESET(OPEN LOOP)RAMP RATE
CLUTCHFILL TIME(VOLUME
RATIO)
TIME TOFULL APPLY
(TFA)
OFF-GOINGCLUTCH
PRESSURECOMMAND 100%
INITIALOFF-GOINGPRESSURE
0%APPLY PRESSUREDECREASING
TURBINESPEED
V01456.01
INITIALONCOMINGPRESSURE
SHIFTINITIATION
CLUTCH HOLD
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Figure 17. Typical 4thGeneration Pushbutton Shift Selectors
R
N
D
R
N
D
R
N
D
SELECT
MONITOR
1 2 3 D N RMODEBUTTON
DISPLAY
MODE INDICATOR(LED)
MODE ID
CONTOURED BEZEL
MODEBUTTON
DISPLAY
MODE INDICATOR(LED)
MODE ID
COMMONSTANDARD COMPACTSTRIP PUSHBUTTONSHIFT SELECTORS
V07178.03.00
1
2
3
4
5
D
N
R
R
N
D
5
4
3
2
1
SIX-SPEED, LEFT-HANDLEVER SELECTOR
HOLD OVERRIDE BUTTON
DISPLAY MODE/DIAGNOSTIC BUTTON
DIGITAL DISPLAY
MODE BUTTON
MODE INDICATOR(LED)
HOLD OVERRIDE BUTTON
DISPLAY MODE/DIAGNOSTIC BUTTON
MODE ID
DIGITAL DISPLAY
MODE BUTTON
MODE INDICATOR(LED)
SIX-SPEED, RIGHT-HANDLEVER SELECTOR
6
1
6
1
6
1
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If communication between the shift selector and TCM
is not valid, both digits will be blanked for up to 12
seconds and then changed to a cateye (-/-). Other
than temporary blanking due to lost communication, ablank display generally means the shift selector has
failed or not powered.
OIL LEVEL DISPLAY
In oil level display mode, transmission fluid level will
be displayed as the number of quarts high or low. If the
proper conditions to measure oil level have been met, a
count down timer or oil level fault code will bedisplayed.
DIAGNOSTIC DISPLAY
In diagnostic mode, the diagnostic codes will be
displayed two digits at a time.
PUSHBUTTON SHIFT SELECTOR(FULL-FUNCTION, NON STRIP-TYPE)
The buttons (refer to Figure 17) available on the
pushbutton selector (including 7-speed) are:
R* hi b l
Down arrow. Pressing the Down arrow wh
in Drive will decrease the highest desired
transmission range by one range down to t
lowest range selection allowed by calibrati(typically 1st). The transmission may exce
the operator requested range to prevent tra
mission or engine damage.
Simultaneously pressing the Up and Down
arrows will change the digital display mod
The display mode sequence is:
Normal operation display
Oil level display (if the transmission is
equipped with an oil level sensor)
Diagnostic display
Normal operation display
Refer to the Operators Manual for specifi
instructions regarding displaying oil level
and diagnostics.
MODEThis button turns on and off a special
input function defined in the calibration.
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If the transmission is held in range due to a DO NOT
SHIFT condition, the left or top display digit will be
blanked and range requests from the pushbutton shift
selector keypad will be ignored by the TCM.
PUSHBUTTON SHIFT SELECTOR(STRIP-TYPE)
The buttons (refer to Figure 17) available on the strip-
type pushbutton shift selector (including 7-speed) are:
R* Press this button to select reverse. The Rbut-
ton will be illuminated and flashed if theshift to reverse is inhibited.
N Press this button to select Neutral.The Nbut-
ton will be illuminated.
D* Press this button to select Drive (forward).
The Dbutton will be illuminated and flashed
if the shift to Drive is inhibited.The trans-
mission will start in the lowest available
range and shift automatically to the highestavailable range depending upon vehicle
operating conditions.
3 (if present)The 3button will be illuminated
and flashed if the forward shift is inhibited
shifts when a damaging or undesirable range
engagement would occur. Some vehicles require
a full apply of the service brakes before a shift
out of Neutral is allowed. Some operationalinhibits require re-selection of the desired
range.
If the transmission is held in range due to a DO NOT
SHIFT condition, the button lights will be turned OFF
and range requests from the shift selector will be
ignored by the TCM.
LEVER SHIFT SELECTOR
The lever shift selector (refer to Figure 18) is an
electro-mechanical control containing a two digit
display (one digit above the other). The operator moves
the lever to select a transmission range. For straight-
through (six ranges) models, the lever shift selector
may have four, five, or six forward range positions,
N(Neutral), and R(Reverse). The 3000 and 4000Product Families 7-speed models may have up to seven
forward range positions. The ranges available on the
shift selector depend upon the shift selector installed
and upon the program in the TCM. The lever shift
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starter until the lever is in the Neutral
position.
D* Press the Hold Override Button if the lever is
in the R(Reverse) or N(Neutral) positionand move the lever to D to select a forward
operation. The highest available forward
range will be displayed in the top digit of the
display when the TCM successfully receives
this selection. The transmission will start in
the lowest available range and shift automat-
ically to the highest available range depend-
ing upon vehicle operating conditions. Theactual transmission range will be displayed
in the bottom digit of the display.
1 through 5Move the lever to the desired for-
ward selector position. Position 1 through 5
are called Preselect positions. The hold
Override Button must be pressedif moving
from Ror Npositions. The highest available
forward range available for each Preselectposition will be displayed in the top digit of
the display when the TCM successfully
receives the selection.
The transmission will start in the lowest
BUTTONis ON or enabled by the TCM. A
mode ID label located above the MODE
BUTTONidentifies the function associate
with the MODE BUTTON. Pressing theMODE BUTTON when the function is OF
will turn ON the function. Pressing the
MODE BUTTON when the function is ON
will turn OFF the function.
Display Mode (button with Allison logo)Press
ing the DISPLAY MODE BUTTONwill
change the digital display mode. The displa
mode sequence is:
Normal operation display
Oil level display (if transmission is
equipped with an oil level sensor
Diagnostic display
Normal operation display
Refer to Section 4 or the Operators Manual for sp
cific instructions regarding displaying oil level an
diagnostics.
If the transmission is held in range due to a DO
NOT SHIFT condition, the top display digit will
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HOLD OVERRIDE UPSHIFT SHIFTSCHEDULE
The hold override upshift shift schedule prevents
engine overspeed by upshifting the transmission intothe next higher range. The hold upshift shift schedule is
not activated unless the transmission is in a range lower
than the highest available range. Hold upshifts occur at
speeds higher than those for normal upshifts.
PRESELECT DOWNSHIFTSHIFT SCHEDULE
The preselect downshift shift schedule permits thedriver to preselect a lower range. The transmission will
downshift when an overspeed condition will not result
after the shift. The downshifts occur at speeds higher
than those at which normal downshifts occur.
Use preselect to enhance vehicle braking and cooling.
Preselect keeps engine speed high which increases
braking effect and engine water flow. Preselect also
enhances the effectiveness and cooling of the hydraulicretarder when descending long grades.
DIGITAL DISPLAY
All shift selectors except the strip-type pushbutton use
The two 10-amp fuses in the VIM protect the main
power to the TCM circuit and the TCM to ignition
circuit. The VIM relays provide switched outputs to a
specific function when actuated by the TCM. Tworelays provide output to the reverse warning and
neutral start circuits and four relays are available for
special function outputs.
Additional circuits from the TCM pass directly through
the VIM and provide power, battery ground, and output
to the electronic speedometer.
THROTTLE POSITIONSENSOR (TPS)
On vehicles not equipped with electronically-
controlled engines, a throttle position sensor (TPS),
which is a sliding resistor sensor (refer to Figure 20), is
attached to the engine fuel control linkage. An analog
TPS is seldom used. However, a discussion of its
operation is provided below.
The sensor is actuated by the mechanical throttle cable
that causes the contacts of the resistor to move along
the resistive strip (refer to Figure 21) and continuously
sends the exact throttle position to the TCM.
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Figure 21. Throttle Position Sliding Resistor Sensor
V00656.01
THROTTLE POSITION LINKAGE
RESISTIVE STRIP
CONTACTS
0 Volt
0.25 Volts
0.972 Volts
CLOSEDTHROTTLE
WIDE OPENTHROTTLE
4.75 Volts
5 Volts
3.889 Volts
APPROX.19 mm (0.75 in.) STROKE
ERRORZONE
ERRORZONE
Adjust so total stroke iswithin8.9 mm35.7 mm band0.97 volts3.889 volts
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Table 1. Movement vs. Voltage
mm (inch) Volts mm (inch) Volts
0 0 24 2.634
1 (0.04) 0.110 25 (0.98) 2.744
2 (0.08) 0.220 26 (1.02) 2.854
3 (0.19) 0.329 27 (1.06) 2.964
4 (0.16) 0.439 28 (1.10) 3.073
5 (0.20) 0.549 29 (1.14) 3.183
6 (0.24) 0.659 30 (1.18) 3.293
7 (0.28) 0.768 31 (1.22) 3.403
8 (0.31) 0.878 32 (1.26) 3.512
9 (0.35) 0.988 33 (1.30) 3.622
10 (0.39) 1.098 34 (1.34) 3.732
11 (0.43) 1.207 35 (1.38) 3.842
12 (1.47) 1.317 36 (1.42) 3.951
13 (0.51) 1.427 37 (1.46) 4.061
14 (0.55) 1.537 38 (1.50) 4.171
15 (0.60) 1.646 39 (1.54) 4.281
16 ()0.63 1.756 40 (1.57) 4.390
The TPS is not used in vehicles equipped with
electronically-controlled engines. On those vehicles, the
throttle position data is sent from the engine electronic
controls directly to the transmission electronic controlsover one of the serial communication links (J1708/
1587, J1939, CAN) or via a PWM signal to the TPS
input. The TCM will autodetect the throttle signal. The
throttle signal can also be set manually via Allison
DOCdiagnostic tools.
SPEED SENSORS
The 3000 and 4000 Product Families transmissionscontain the following speed sensors (refer to
Figure 23):
Engine
Turbine
Output
Figure 22 shows the current speed sensors in use.
The TCM processes speed sensor and TPS data to:
Determine proper shift points
Monitor the current range
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The signal wires from the sensor are formed as twisted
pairs to cancel magnetically induced fields. Noise from
other sources is eliminated by using two-wire
differential inputs at the TCM.
ENGINE SPEED SENSORS
Engine speed sensors (Figure 23) are externally
mounted in the torque converter housing, directed at
the ribs protruding from the torque converter.
TURBINE SPEED AND OUTPUT
SPEED SENSORS
3000 PRODUCT FAMILY TRANSMISSIONS
(EXCEPT 7-SPEED MODELS)
The turbine speed sensor (refer to Figure 23) is
mounted in the control module, directed at ribs
protruding from the rotating clutch module.
The output speed sensor is externally mounted in the
rear cover or in the retarder housing, if so equipped.
The output speed sensor is directed at the teeth of a
Figure 23. Speed Sensors
TURBINE3000 PRODUCT FAMILY
OUTPUT3000 PRODUCT FAMILY
7-SPEED
TURBINE4000 PRODUCT FAMILY
OUTPUT ALL EXCEPTNEW RETARDER UNITS
ENGINE ALL
V08593.01.00
OUTPUT(NEW RETARDER)
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SCI (J 17081/J1587)CONNECTOR
(OPTIONAL)
VEHICLEINTERFACEMODULE(VIM)
TRANSMISSIONCONTROLMODULE(TCM)
REMOTE LEVERSELECTOR
COMPACTPUSHBUTTONSELECTOR
SHIFTSELECTOR
VIW
CONNECTOR(OPTIONAL)
VIMCONNECTOR
ALLISON DOC
DIAGNOSTICTOOL
CONNECTOR
TRANSFER CASE CONNECTOR
(3
000 PRODUCT FAMILY 7 SPEED)
OUTPUTSPEED SENSORCONNECTOR
SENSOR HARNESSCONNECTOR (OPTIONAL)
RETARDER ACCUMULATORCONNECTOR
J1939CONNECTOR
RETARDERMODULATION
REQUEST (RMR)CONNECTOR
DEUTSCH 9-PINDIAGNOSTIC TOOL
CONNECTOR
FOR PC
ALLISON DOCFOR PDA
TCMCONNECTOR
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VEHICLE COMMUNICATIONS
INTERFACES
J1939 INTERFACE
This is a high-speed real time interface (refer to
Figure 25) which allows the TCM to communicate with
Transmission Output Speed
Engine rpm
Range Position Selected
Actual Range Attained
Lockup Clutch Status
Figure 25. J1939 Network Configuration
Stubs must bespaced at least10 cm apart
UNUSED
STUBA stubtees offthe backbone,and includes allwiring to the node.The total stubmustbe 1 meter or less.
ENGINE
CONTROLLER
All unused stubs mustbe covered with caps.
TCM IN-CAB DIAGNOSTIC
BLOCKHEAD HOUSING
V08750.00.00
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Table 2. Input Functions Listed By Vocational Models
Input Functions
Y = Yes
N = No
X = Available
= Not Available
Vocational Models
Emergency
VehicleSeries
Motorhome
Pupil
Transport/
ShuttleSeries
SpecialSeries
BusSeries
HighwaySeries
RuggedDutySeries
TruckBased
RecreationalSeries
Available
Normally
Activated
Available
Normally
Activated
Available
Normally
Activated
Available
Normally
Activated
Available
Normally
Activated
Available
Normally
Activated
Available
Normally
Activated
Available
Normally
Activated
A. Secondary Mode Input X Y X Y X Y X Y X Y X Y X Y X Y
B D 1 S l i X Y X Y X Y X Y X Y X Y X Y X Y
data is properly identified and formatted so information
is recognizable by other users of the link. Pin 46 of the
TCM 80-way connector carries this function.
SPECIAL INPUT AND OUTPUT
FUNCTIONS
Special vocational requirements can be satisfied using
the special input and output features. Most of the input
functions are activated and deactivated by switched
power or signal ground to the TCM. Some functions
may also be activated by the MODEbutton on the shift
selector. Special output functions are typicallycontrolled by the TCM-switching, customer-supplied
relays that are not a part of the VIM.
Typical input and output functions are listed by
vocational model in Tables 2 and 3 respectively.
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Z. Retarder Enable X Y X Y X Y X Y X Y X Y X Y X Y
AA.Service Brake Status X Y X Y X Y X Y X Y X Y X Y X Y
AF. Differential Clutch Request X Y Y X Y X Y X Y X Y X Y X Y
AG.Automatic NeutralDual
Input
X Y Y X Y X Y X Y X Y X Y X
AH.Kickdown X Y X Y X Y X Y X Y X Y X Y
AI. Military Aux. Function
Range Inhibit (Standard)
X N X N
AJ. 4thLockup Pump Mode X N X N X N X N X N X N X N X N
Table 2. Input Functions Listed By Vocational Models(contd)
Input Functions
Y = Yes
N = No
X = Available
= Not Available
Vocational Models(contd)
Emergency
VehicleSeries
Motorhome
Pupil
Transport/
ShuttleSeries
SpecialSeries
BusSeries
HighwaySeries
RuggedDutySeries
TruckBased
RecreationalSeries
A
vailable
N
ormally
A
ctivated
A
vailable
N
ormally
A
ctivated
A
vailable
N
ormally
A
ctivated
A
vailable
N
ormally
A
ctivated
A
vailable
N
ormally
A
ctivated
A
vailable
N
ormally
A
ctivated
A
vailable
N
ormally
A
ctivated
A
vailable
N
ormally
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Table 3. Output Functions Listed By Vocational Models
output fu3nctions
Y = Yes
N = No
X = Available
= Not Available
Vocational Models
Emergency
VehicleSeries
Motorhome
Pupil
Transport/
ShuttleSeries
SpecialSeries
BusSeries
HighwaySeries
RuggedDutySeries
TruckBased
RecreationalSeries
Available
Normally
Act
ivated
Available
Normally
Act
ivated
Available
Normally
Act
ivated
Available
Normally
Act
ivated
Available
Normally
Act
ivated
Available
Normally
Act
ivated
Available
Normally
Act
ivated
Available
Normally
Act
ivated
A. Engine Enable X Y X Y X Y X Y X Y X Y X Y X Y
B. Sump/Retarder
Temperature Indicator
X Y X Y X Y X Y X Y X Y X Y X Y
C. Range Indicator X Y X Y X Y X Y X Y X Y X Y X Y
D. Output Speed Indicator A X Y X Y X Y X Y X Y X Y X Y X Y
E. Output Speed Indicator B X Y X Y X Y X Y X Y X Y X Y X Y
G. PTO Enable X Y X Y X Y X Y X Y X Y X Y X Y
I. Engine Overspeed Indicator X Y X Y X Y X Y X Y X Y X Y X Y
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WIRING HARNESSES
EXTERNAL WIRING HARNESS
The transmission uses external wiring harnesses to connectthe various electronic system components. These external
harnesses are supplied by the vehicle manufacturer. A
typical 4thGeneration Controls wiring harness and
electronic components are illustrated in Figures 24.
Control system configuration for various vocations
may be adapted to operator needs and to vehicle
requirements. The basic harness provides connection
to the TCM from the following:
Vehicle interface wiring and the vehicle interfa
module Diagnostic tool connector
Shift selector
J1939 Controller Area Network (CAN)
Transmission connectors (feedthrough harness
speed sensors, etc.
Throttle Position Sensor (TPS) (seldom used)
PCS1 (C1)
TCC (LOCKUP)
PCS2 (C2/C3)PS1 DIAGNOSTIC
PRESSURE SWITCHNT1 TURBINE
SPEED SENSOR(3000 ONLY)
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3000 and 4000 Product Families transmissions (except
7-speed) equipped with an output retarder have
additional connectors for:
Retarder control
Retarder accumulator
Retarder temperature
Output speed sensor
Vehicles using a secondary shift selector require an
additional connector for the second shifter.
INTERNAL WIRING HARNESS
The internal wiring harness (refer to Figure 26)
provides connection between the external harness and
the:
Internal solenoids
Turbine speed sensor (3000 Product Family only)
PS1 pressure switch
Transmission fluid level sensor
Sump temperature sensor
TRANSID (TIDA)
The TransID feature (refer to Figure 27) has been
developed to allow the TCM to automatically
determine certain transmission configurations and to
adjust the calibration accordingly. This will allow
Allison Transmission to make minor changes and
improvements that affect calibration without
requiring precise coordination of new TCM
calibrations with transmission changes. In general,
TCMs with calibrations for a new transmission
configuration will be shipped several months prior totransmission shipment. This should make sure that
when a TCM is mated with the new transmission, the
appropriate calibration will be available. In many
cases, the part numbers of the transmission and
calibrated TCM will not be changed. This will reduce
the need for customers to use cross-referenced lists
of transmission and calibrated TCM assemblynumbers when transmission changes are made.
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When a TCM with an older calibration is mated with a
new transmission, a diagnostic code will be logged.
Recalibrating the TCM is generally all that is required
to resolve the incompatibility. Customers can continueto order specific transmission assembly numbers and
calibrated TCM assembly numbers and receive all
changes made to the transmissions and all calibrations
needed. This will reduce the number of assembly
number changeovers with which a customer must
contend as changes are incorporated into Allison
transmissions.
Figures 28 through 30 show the resistance vs.
temperature relationship for the ON/OFF solenoid,
pressure control solenoid, and retarder air solenoid,
respectively, associated with TIDA.
6.00
5.50
5.00
4.50
4.00
SolenoidRe
sistance
3.50
3.00
2.50
Min OhmsMax Ohms
Resistance Vs. Temperature
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Figure 29. Pressure Control Solenoid
S
olenoidResistance
Temperature
3.50
4.00
4.50
5.00
5.50
6.00
6.50
7.00
7.50
8.00
-4 32 68 104 140 176 212 248 284 Degrees F
Min Ohms
Max Ohms
Degrees C-20 0 20 40 60 80 100 120 140
Resistance Vs. Temperature
V09264.00.01
Section FouELECTRONIC DIAGNOSTICS
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One of the advanced electronic features of the Allison
4thGeneration transmissions is diagnostic capability.
Using the digital diagnostic codes, an operator or
service mechanic can isolate the nature, course, andseverity of a problem when it first occurs. This
capability reduces the time and cost of troubleshooting
the transmission if a problem should arise.
NOTE:
The diagnostic tests described in this section are
dependent upon information from the speed sen-
sors. Diagnostic codes indicating a condition
requiring correction may be due to faulty speed
sensors when no mechanical cause appears to be
present.
RANGE/SHIFT TESTS
During each shift the TCM performs tests to check
the transmission range and to verify that a shift is
being made properly. These tests are (refer to
Figure 31):
Range verification
Solenoid stuck ON Solenoid stuck OFF
PS1 pressure switch
RANGE VERIFICATION
Range verification is continuously tested (refer to
Figure 31) when a shift is not in progress. Range
verification verifies that the current range attained is trange commanded by the TCM. The test checks the
current gear ratio by comparing the turbine and outp
speeds. This speed ratio is then compared to the spee
ratio (stored in memory) of the range the TCM has
commanded.
If the two ratios do not match, a diagnostic code is
logged and the TCM commands an appropriate
response to the condition.
PULL DOWN
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SOLENOID STUCK ON TEST
The off-going ratio test (refer to Figure 31) is
performed while a shift is in progress. Within a set time
after a shift has been commanded, the TCM determinesthe ratio between turbine speed and output speed. The
speed ratio is compared to the speed ratio of the
previous range. If the previous speed ratio is still
present after a period of time, the TCM assumes the
off-going clutch did not release. The shift will be tried
twice to verify the condition. If the previous speed ratio
is still present, a diagnostic code is logged and the
TCM commands the transmission to the previousrange.
The off-going ratio test is applied during the interval
between the turbine speed Shift Initiation point and the
Pull Down Detected point.
SOLENOID STUCK OFF TEST
The oncoming ratio test (refer to Figure 31) isperformed near the end of a shift in progress. The
oncoming ratio test checks turbine speed and output
speed to determine if the transmission is in the range
commanded by the TCM When the ratios do not
The TCM also uses PS1 to verify that the C1 and C2
latch valves are in the correct position in second
through sixth range. PS1 pressurizes when both latch
valves are stroked downward, and exhausts when either
latch valve is de-stroked (stroked upward). Using PS1s
signal, the TCM checks that both latch valves are
stroked down after shifting into second range and that
the two latch valves remain in that position while in
second through fifth ranges. The TCM also checks that
the C1 latch valve moves to the de-stroked position
after shifting into sixth range. If the TCM detects PS1
in an incorrect state, i.e. switch exhausted in second
through fifth range, or switch pressurized in sixthrange, then the TCM will set a diagnostic code.
CHECK TRANS LIGHT
The electronic control system is programmed to inform
the operator of a problem with the transmission system
and automatically take action to protect the operator,
vehicle, and transmission. To do this, the TCM restricts
shifting, turns on the CHECK TRANSlight on theinstrument panel, and registers a diagnostic code.
NOTE:
For some problems diagnostic codes may be regis-
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performing as designed and is operating with reduced
capabilities. Before turning the ignition off, the
transmission may be operated for a short time in the
attained range to limp home for service assistance.
Service should be performed immediately to minimize
the potential for damage to the transmission.
When the CHECK TRANSlight comes on and the
ignition switch is turned off, the transmission will
remain in N(Neutral) until the CHECK TRANSlight
is cleared.
Generally, while the CHECK TRANSlight is on,
upshifts and downshifts will be restricted and directionchanges (DR, RD) will not occur. The lockup clutch
is disengaged when transmission shifting is restricted
or during any critical transmission malfunction.
DIAGNOSTIC TOOLS
Allison DOC diagnostic tools (refer to Figure 32) are
used to assist in installation and troubleshooting.However, Allison DOCfor PDAService Tool canonly read data and codes.
DIAGNOSTIC CODES
Diagnostic codes are numerical reports of malfunctio
in transmission operation. A diagnostic code consist
of a letter (C, P, or U) and four digits (example, P097These codes are logged in a list in the TCM memory
with the most severe or otherwise most recent code
listed first.
When accessing codes via the shift selector, only fiv
can be displayed at any time and each has a designati
such as D1, D2......D5. If a new code is logged into t
memory, it will replace the oldest non-active code in
the display. If all five of the existing displayed codesare active, the code with the lowest priority that is no
included on the severity list is dropped from the
display. Access to the diagnostic codes and code
information is through one of the following:
Pushbutton and lever shift selectors
Allison DOCdiagnostic tools
Vehicle manufactures diagnostic tool
The TCM separately stores the active and historical
(non-active) codes. An active code is any code that i
current in the TCM decision-making process.
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PUSHBUTTON SHIFT SELECTOR
(Full-Function, Non Strip-Type)
Bring the vehicle to a stop at a safe location.
Apply the parking brake.
TO DISPLAY STORED CODES
To display a code such as P0974, simultaneously
press the (Up) and (Down) arrow buttons (refer
to Figure 17) once to access the diagnostic display
mode (twice if an oil level sensor is installed) or
press the MODEbutton once (twice if an oil
level sensor is installed).
The display will first read D 1, next will be a
blank and P, next will be 0 9, and last will be 7 4.
It will continue to rotate through this sequence
until the (Up) and (Down) arrows or MODE
button is press.
When the (Up) and (Down) arrows or the
MODEbutton is pressed, the next code will dis-
play starting with D 2 and rotate through the next
code in the same sequence as above.
LEVER SHIFT SELECTOR
Bring the vehicle to a stop at a safe location.
Apply the parking brake.
TO DISPLAY STORED CODES
To display a code, press the MODE button (refer
to Figure 18) once to access the diagnostic dis-
play mode (twice if an oil level sensor is
installed).
The lever shift selector has a two digit displaywith one digit above the other (refer to
Figure 18).
To display a code such as P0974, the lever shift
selector display will first read D above 1, indicat-
ing the first position. Next will be a blank display
above P. Then 0 above 9 will display, and the last
display will be 7 above 4. It will continue to
rotate through this sequence until the MODEbutton is pr