98 pickup transfer exploded view

TRANSFER CASE DISASSEMBLY

1. Remove drain plug and drain transfer case fluid. Remove 3 bolts securing motor/encoder and gasket to transfer case. See Fig. 2 . Remove "O" ring and transfer case vent tube from transfer case. Vent tube removal is only necessary if tube is damaged. Remove 2 rear speed sensors from rear case. See Fig. 3 .

2. Remove rubber plug from rear case. See Fig. 3 . Spread rear output bearing retaining ring from mainshaft through access hole under rubber plug. Retaining ring must be spread to separate front and rear cases. Remove front speed sensor from front case. See Fig. 4 . Remove 6 input shaft studs from front case. See Fig. 5 . Remove 2 studs securing transfer case shield mounting bracket to transfer case. See Fig. 6 .

NOTE: Exploded view of transfer case is not available. Note location of transfer case bolts and studs prior to disassembling transfer case. Bolts and studs MUST be installed in same locations as removed.

1998 Chevrolet Pickup K3500

1998 TRANSFER CASES' 'General Motors Corp. New Venture 246 Overhaul



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Thursday, March 25, 2010 8:35:53 PM © 2005 Mitchell Repair Information Company, LLC.

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Thursday, March 25, 2010 8:35:56 PM Page 1 © 2005 Mitchell Repair Information Company, LLC.

Fig. 2: Locating Motor/Encoder & Gasket Courtesy of GENERAL MOTORS CORP.



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Fig. 3: Locating Rear Speed Sensors & Rubber Plug Courtesy of GENERAL MOTORS CORP.



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Fig. 4: Locating Front Speed Sensor Courtesy of GENERAL MOTORS CORP.



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Fig. 5: Removing & Installing Input Shaft Studs (6) Courtesy of GENERAL MOTORS CORP.



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Fig. 6: Removing & Installing Transfer Case Shield Mounting Bracket Courtesy of GENERAL MOTORS CORP.

3. Note location of all case bolts, studs and washers (if equipped). Remove case bolts, studs and washers (if equipped) from front and rear case. Remove rear case from front case. During disassembly of rear case from front case, rear output bearing retaining ring must be spread open to allow case separation. Use a rubber mallet to separate case halves while spreading rear output bearing retaining ring. Remove 2 case alignment dowels from front case. See Fig. 7 .

4. Remove oil pump retainer tab from rear case. See Fig. 8 . Remove rear output bearing retaining ring from mainshaft. Remove rear output bearing from mainshaft. Remove tone wheel from mainshaft. See Fig. 9 . Remove magnet from front case. See Fig. 10 . Remove oil pump pickup tube from oil pump inlet hole and "O" ring. See Fig. 11 .

5. Remove oil screen from front case. Remove oil screen from nylon tube. See Fig. 11 . Remove oil pump from mainshaft. Remove oil pump "O" ring from oil pump inlet hole. See Fig. 12 . Remove gerotor pump retaining ring from mainshaft. See Fig. 13 . Remove drive and driven sprocket retaining rings from mainshaft and output shaft. See Fig. 14 .



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Fig. 7: Removing & Installing Alignment Dowels Courtesy of GENERAL MOTORS CORP.



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Fig. 8: Removing & Installing Oil Pump Retainer Tab Courtesy of GENERAL MOTORS CORP.



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Fig. 9: Locating Tone Wheel, Output Bearing & Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 10: Removing & Installing Front Case Magnet Courtesy of GENERAL MOTORS CORP.



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Fig. 11: Removing & Installing Oil Screen & Tubes Courtesy of GENERAL MOTORS CORP.



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Fig. 12: Removing & Installing Oil Pump "O" Ring Courtesy of GENERAL MOTORS CORP.

Fig. 13: Removing & Installing Gerotor Pump Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 14: Removing & Installing Drive & Driven Sprockets, Chain & Retaining Rings Courtesy of GENERAL MOTORS CORP.

6. Remove chain with drive and driven sprockets from mainshaft and output shaft. Remove drive and driven sprockets from chain. Remove mainshaft from front case. Remove clutch retaining ring from mainshaft. See Fig. 15 .

7. Remove thrust bearing and inner and outer bearing support plates from mainshaft and inner clutch drum. Using a press, remove inner bearing support plate from thrust bearing. See Fig. 16 . Remove all inner clutch plates and outer separator plates. Note number and location of plates. Remove clutch drum flange. See Fig. 17 .

8. Remove clutch inner drum retaining ring. Remove clutch return spring from mainshaft and clutch inner drum. See Fig. 18 . Remove clutch inner drum from mainshaft and clutch drum. See Fig. 19 . Remove clutch drum from mainshaft. See Fig. 20 . Using a press, remove clutch drum inner and outer bearings from clutch drum. See Fig. 21 and Fig. 22 .



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Fig. 15: Removing & Installing Clutch Retaining Ring Courtesy of GENERAL MOTORS CORP.

Fig. 16: Removing & Installing Inner & Outer Support Plates Courtesy of GENERAL MOTORS CORP.



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Fig. 17: Removing & Installing Clutch Drum Flange Courtesy of GENERAL MOTORS CORP.



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Fig. 18: Removing & Installing Clutch Return Spring Courtesy of GENERAL MOTORS CORP.



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Fig. 19: Removing & Installing Clutch Inner Drum Courtesy of GENERAL MOTORS CORP.



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Fig. 20: Removing & Installing Clutch Drum Courtesy of GENERAL MOTORS CORP.



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Fig. 21: Removing & Installing Clutch Drum Bearing (Inner) Courtesy of GENERAL MOTORS CORP.



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Fig. 22: Removing & Installing Clutch Drum Bearing (Outer) Courtesy of GENERAL MOTORS CORP.

9. Remove clutch lever and 2 clutch lever inserts from front case. See Fig. 23 . Remove shift rail from range fork. See Fig. 24 . Remove poppet plunger, poppet spring, poppet bolt "O" ring and poppet bolt from front case. See Fig. 25 .

10. Remove range fork and range shift sleeve from planetary gear. See Fig. 26 . Remove range shift sleeve from range fork. See Fig. 27 . Remove front input gear oil seal from front case. See Fig. 28 .

11. Using snap ring pliers, remove front input gear case bearing retaining ring from front input gear. See Fig. 29 . During removal of retaining ring, DO NOT scratch or damage seal surface area of front input shaft with retaining ring.



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12. Remove output shaft front oil seal. See Fig. 30 . Remove output shaft retaining ring from output shaft. See Fig. 31 . DO NOT scratch or damage oil seal surface of output shaft when removing retaining ring. Remove output shaft from front case. See Fig. 32 .

13. Remove tone wheel from output shaft. See Fig. 33 . Remove cap from output shaft. See Fig. 34 . Remove planetary gear with input shaft from front case. See Fig. 35 . Using a press, remove pilot bearing from input shaft. See Fig. 36 . Remove thrust plate retaining ring from planetary gear and input shaft. See Fig. 37 . Remove thrust plate from planetary gear and input shaft. See Fig. 38 .

14. Remove thrust washer from planetary gear and input shaft. See Fig. 39 . Remove input gear from planetary gear. See Fig. 40 . Remove thrust washer from planetary gear. See Fig. 41 . Remove rear output bearing retaining ring from rear case. See Fig. 42 .

15. Remove oil fill plug from rear case. Remove output shaft rear bearing from rear case. See Fig. 43 . Remove output shaft seal from rear case. See Fig. 44 . Drive out rear retaining bushing from rear case. See Fig. 45 .

16. Remove sector shaft and sector retaining ring from front case. See Fig. 46 . Remove sector from front case. See Fig. 47 . Remove sector bearing from front case. See Fig. 48 .

17. Remove front output shaft bearing retaining ring from front case. Press out front output shaft bearing from front case. See Fig. 49 . Remove input gear bearing retaining ring from inside of front case. See Fig. 50 . Press out input gear bearing from front case. See Fig. 51 .

Fig. 23: Removing Clutch Lever & Inserts Courtesy of GENERAL MOTORS CORP.



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Fig. 24: Removing & Installing Shift Rail Courtesy of GENERAL MOTORS CORP.



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Fig. 25: Removing & Installing Poppet Components Courtesy of GENERAL MOTORS CORP.



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Fig. 26: Removing & Installing Range Fork & Range Shift Sleeve Courtesy of GENERAL MOTORS CORP.



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Fig. 27: Removing & Installing Range Shift Sleeve Courtesy of GENERAL MOTORS CORP.



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Fig. 28: Removing & Installing Input Gear Oil Seal Courtesy of GENERAL MOTORS CORP.



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Fig. 29: Removing & Installing Case Bearing Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 30: Removing & Installing Output Shaft Oil Seal Courtesy of GENERAL MOTORS CORP.



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Fig. 31: Removing & Installing Output Shaft Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 32: Removing & Installing Output Shaft Courtesy of GENERAL MOTORS CORP.



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Fig. 33: Removing & Installing Tone Wheel Courtesy of GENERAL MOTORS CORP.



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Fig. 34: Removing & Installing Output Shaft Cap Courtesy of GENERAL MOTORS CORP.



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Fig. 35: Removing & Installing Planetary Gear & Input Shaft Courtesy of GENERAL MOTORS CORP.



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Fig. 36: Removing & Installing Pilot Bearing Courtesy of GENERAL MOTORS CORP.



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Fig. 37: Removing & Installing Planetary Gear Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 38: Removing & Installing Thrust Plate Courtesy of GENERAL MOTORS CORP.



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Fig. 39: Removing & Installing Input Shaft Thrust Washer Courtesy of GENERAL MOTORS CORP.



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Fig. 40: Removing & Installing Input Gear Courtesy of GENERAL MOTORS CORP.



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Fig. 41: Removing & Installing Planetary Gear Thrust Washer Courtesy of GENERAL MOTORS CORP.



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Fig. 42: Removing & Installing Bearing Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 43: Removing & Installing Output Shaft Rear Bearing Courtesy of GENERAL MOTORS CORP.



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Fig. 44: Removing & Installing Output Shaft Seal Courtesy of GENERAL MOTORS CORP.



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Fig. 45: Removing & Installing Rear Case Bushing Courtesy of GENERAL MOTORS CORP.



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Fig. 46: Removing & Installing Sector Shaft Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 47: Removing & Installing Sector At Front Case Courtesy of GENERAL MOTORS CORP.



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Fig. 48: Removing & Installing Sector Bearing At Front Case Courtesy of GENERAL MOTORS CORP.



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Fig. 49: Removing & Installing Output Shaft Bearing At Front Case Courtesy of GENERAL MOTORS CORP.



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Fig. 50: Removing & Installing Input Gear Bearing Retaining Ring Courtesy of GENERAL MOTORS CORP.



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Fig. 51: Removing & Installing Input Gear At Case Bearing Courtesy of GENERAL MOTORS CORP.

CLUTCH PACK SHIM PROCEDURE

1. With clutch drum assembled and installed on mainshaft, position rear section of mainshaft through hole of a flat fixture or surface. See Fig. 52 . Fixture must have a machined flat surface. Hole in fixture should be large enough to allow mainshaft to fit through hole with bottom of clutch drum sprocket flange resting on flat surface.

NOTE: Ensure clutch drum has all inner clutch plates and outer separator plates required for clutch drum. NV 246 transfer case has 10 clutch plates and 10 outer separator plates. Ensure existing clutch plate shim(s) are not installed in clutch drum.



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2. Using a micrometer, measure thickness of machined flat disk. See Fig. 53 . Record this measurement. Take 2 additional disk measurements 120 degrees apart from each other and record these measurements. Take average of 3 recorded measurements.

3. Use this average as thickness measurement of machined flat disk. Position a flat disk over top of mainshaft and rest on top inner clutch plate. To ensure accurate measurement, disk must be machined round and flat. Ensure flat disk is resting on top of inner clutch plate only, and not resting on clutch inner drum.

4. Ensure bottom of clutch drum sprocket flange is resting on flat surface. See Fig. 53 . There should be a small gap between flat disk and clutch drum. Position 100 lbs. of weight disks on top of flat disk. Weight being used may vary no more than plus or minus 10 percent. Weight disks do not need to be machined round or flat.

5. Using a height gauge, measure from top of flat disk to flat machined fixture surface. See Fig. 54 . Record this measurement. Take 2 additional measurements 120 degrees apart from each other and record these measurements. Take average of 3 recorded measurements. Use this average as distance measurement from top of flat disk to flat machined fixture surface.

6. Note measurement from top of flat disk to flat machined fixture surface. Subtract flat disk thickness from this measurement. Remaining distance is clearance between top of clutch drum and inner clutch plate. Clearance should be 4.025-4.035" (102.24-102.49 mm). Remove weight disks and flat disk. Add shims to top of inner clutch plate as necessary to ensure required clearance is met. See Fig. 55 . Repeat procedure with shims installed to ensure clearance is correct.



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Fig. 52: Installing Mainshaft With Clutch Drum On Fixture Courtesy of GENERAL MOTORS CORP.



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Fig. 53: Installing Flat Disk & Weight Disks Courtesy of GENERAL MOTORS CORP.



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Fig. 54: Measuring Distance Between Flat Disk & Fixture Surface Courtesy of GENERAL MOTORS CORP.



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Fig. 55: Adding Shims To Clutch Drum For Clearance Courtesy of GENERAL MOTORS CORP.



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98 pickup transfer exploded view

Documents

disassembling transfer

transfer case fluid

case separation

disassembly of rear

transfer case vent tube

exploded view of transfer

rear cases

case alignment dowels