Tools Required

1. Remove the gearshift lever case from the transmission. Refer to Gearshift and Select Shaft Assembly Replacement .
2. Remove the transfer case from the vehicle. Refer to Transfer Case Replacement in Transfer Case.
3. Remove the following items from the transmission:

•	The twelve bolts.

•	The rear case.




4. Remove the rear case oil seal (2) from the rear case (1) using the J 29369 with the J 23907 .



5. Remove the rear case countershaft plug (2) from the rear case (1) using the J 35664 and a hammer.
6. Clean the rear case and the transmission mating surfaces.
7. Clean the gearshift lever case and the rear case mating surfaces.
8. Inspect the rear case for cracks or porosity. If cracks or porosity exist, replace rear case.

1. Install the rear countershaft plug (1) into the rear case (2) using the J 37758 and the J 8092 and a hammer.



2. Install the new rear case oil seal (1) into the rear case (2) using the J 37750 and a hammer.
3. Apply the J 36850 to the new rear case oil seal lip.
4. Apply the GM P/N 12346240, or equivalent, to the transmission rear case mating surface.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

5. Install the rear case to the transmission and secure with the twelve bolts.

Tighten
Tighten the rear case bolts to 28 N·m (20 lb ft).

6. Install the transfer case into the vehicle.
7. Install the gearshift lever case to the transmission. Refer to Gearshift and Select Shaft Assembly Replacement .
8. Add approximately 1.5 liters (1.6 quarts) of 75W-90 GL4 lubricant or equivalent, into the transmission oil level/filler plug hole. The oil level should be even with the bottom of the transmission oil level/filler plug hole.
9. Apply the GM P/N 12346004, or equivalent, to the threaded portion of the transmission oil level/filler plug.



10. Install the transmission oil level/filler plug (2) into the transmission.

Tighten
Tighten the transmission oil level/filler plug to 28 N·m (20 lb ft).