GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Astro - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 Transfer Case Replacement

Removal Procedure
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Remove the front propeller shaft. Refer to Front Propeller Shaft Replacement in Propeller Shaft.
  3. Remove the rear propeller shaft. Refer to Rear Propeller Shaft Replacement in Propeller Shaft.
  4. Remove the vent hose from the transfer case.
  5. Disconnect the vehicle speed sensor electrical connectors.
  6. Remove the electrical connectors from the transfer case motor/encoder.
  7. Remove any wiring harness from the transfer case.
  8. Support the transfer case with a transmission jack.

    9. Object Number: 422448 Size: SH
  9. Remove the bolt andf washer securing the support brace to the transmission.

    10. Object Number: 422453 Size: SH
  10. Remove the two bolts securing the support brace to the transfer case.

    11. Object Number: 422440 Size: SH
  11. Remove two bolts and washers securing the transfer case adapter to the mount.

    12. Object Number: 396823 Size: SH
  12. Remove the six bolts securing the transfer case and bracket to the transmission adaptor.
  13. Remove the transfer case.
    14. • Start by pulling the transfer case straight back from the transmission.
    • After the transfer case is pulled out from the transmission turn and lower the transfer case.
  14. Remove and discard the gasket.

Installation Procedure
  1. Install a new gasket to the transmission. Use sealer GM P/N 12346004 in order to hold the gasket in place.
  2. Raise and position the transfer case to the vehicle

    3. Object Number: 396823 Size: SH

    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.

  3. For vehicles equipped with a automatic transmission, install the six bolts securing the transfer case and bracket to the transmission adaptor.

    4. Tighten
    Tighten the bolts to 47 N·m (35 lb ft).


    Object Number: 422440 Size: SH
  4. Remove two bolts and washers securing the transfer case adapter to the mount.

    5. Object Number: 422448 Size: SH
  5. Install the bolt securing the support brace to the transmission.

    6. Tighten
    Tighten the bolt to 128 N·m (94 lb ft).


    Object Number: 422453 Size: SH
  6. Install the two bolts securing the support brace to the transfer case.

    7. Tighten
    Tighten the bolt and stud to 90 N·m (66 lb ft).


    Object Number: 416724 Size: SH
  7. Install the vent hose to the transfer case.
  8. Check the transfer case oil level. Refer to Oil Replacement .
  9. Connect the speed sensor electrical connectors.
  10. Install the electrical connectors to the transfer case motor/encoder.
  11. Install any wiring harness to the transfer case.
  12. Install the rear propeller shaft. Refer to Rear Propeller Shaft Replacement in Propeller Shaft.
  13. Install the front propeller shaft. Refer to Front Propeller Shaft Replacement in Propeller Shaft.
  14. Lower the vehicle.