GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Astro - 4WD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Case Extension Assembly

Removal Procedure
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Disconnect the vehicle speed sensor electrical connector.

    3. Object Number: 97102 Size: SH
  3. Remove the vehicle speed sensor bolt from the case extension.
  4. Remove the seal from the case extension.
  5. Remove the propeller shaft. Refer to one of the following procedures:
    6. • Refer to Propeller Shaft Replacement (Rear) In Driveline Axle.
    • Refer to Propeller Shaft Replacement (Front) In Driveline Axle.

    Object Number: 97258 Size: SH
  6. Remove the transmission mount nut and washer.
  7. Support and raise the transmission slightly, using the transmission jack.
  8. Remove the transmission mount bolts.
  9. Remove the transmission mount and shims, if present.

    10. Object Number: 13158 Size: SH
  10. Remove the case extension bolts (32).
  11. Remove the case extension (31) with the seal (30).
  12. Remove the vehicle speed sensor from the case extension if necessary.

Installation Procedure

    Object Number: 13158 Size: SH
  1. Install the case extension (31) with a new seal (30).

    2. 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.

  2. Install the bolts (32).

    3. Tighten
    Tighten the bolts to 35 N·m  (26 lb ft).


    Object Number: 97258 Size: SH
  3. Install the transmission mount and shims, if present.
  4. Install the transmission mount bolts.

    5. Tighten
    Tighten the bolts to 34 N·m  (25 lb ft).

  5. Lower the transmission.
  6. Install the transmission mount nut and washer.

    7. Tighten
    Tighten the nut to 41N·m  (30 lb ft).

  7. Install the propeller shaft. Refer to one of the following procedures:
    8. • Refer to Propeller Shaft Replacement (Rear) In Driveline Axle.
    • Refer to Propeller Shaft Replacement (Front) In Driveline Axle.

    Object Number: 97102 Size: SH
  8. Install the vehicle speed sensor and seal to the case extension.
  9. Install the vehicle speed sensor bolt.

    10. Tighten
    Tighten the bolt to 11N·m  (97 lb in).

  10. Install the speed sensor electrical connector.
  11. Lower the vehicle.