GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 21426 Extension Housing Seal Installer

Removal Procedure


    Object Number: 656358  Size: SH
  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Remove the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.
  3. Remove the rear axle torque arm. Refer to Torque Arm Replacement in Rear Suspension.
  4. Remove the catalytic converter hanger.
  5. Remove the case extension bolts (1).
  6. Remove the case extension (2).
  7. Remove the case extension O ring (3). Discard the O ring (3).

  8. Object Number: 408509  Size: SH
  9. Remove the case extension seal.

  10. Object Number: 481935  Size: SH
  11. Remove the output shaft sleeve (1), if necessary.
  12. Remove the output shaft seal (2), if necessary.

Installation Procedure


    Object Number: 481935  Size: SH
  1. Install the output shaft sleeve seal (2), if necessary.
  2. Install the output shaft sleeve (1) using J 21426 , if necessary.

  3. Object Number: 647512  Size: SH
  4. Install a new case extension seal using a soft face hammer and J 21426 .

  5. Object Number: 656358  Size: SH
  6. Install a new case extension O ring (3).
  7. Install the case extension (2).
  8. 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.

  9. Install the case extension bolts (1).
  10. Tighten
    Tighten the case extension bolts (1) to 35 N·m (26 lb ft).

  11. Install the rear axle torque arm. Refer to Torque Arm Replacement in Rear Suspension.
  12. Install the propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.
  13. Install the catalytic converter hanger.
  14. Lower the vehicle.
  15. Check the transmission fluid level.