GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 Transfer Case Assembly Replacement

Removal Procedure

    Object Number: 648043 Size: SH
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Remove the transfer case shield from the crossmember. Refer to Transfer Case Shield Replacement .
  3. Remove the brace from the transfer case left side shown, if equipped.
  4. Drain the transfer case of fluid. Refer to Transfer Case Fluid Replacement .
  5. Remove the rear propeller shaft from the vehicle.
    6. • For vehicles equipped with the one piece propeller shaft, refer to One-Piece Propeller Shaft Replacement in Propeller Shaft.
    • For vehicles equipped with the two piece propeller shaft, refer to Two-Piece Propeller Shaft Replacement in Propeller Shaft.
  6. Remove the front propeller shaft from the vehicle. Refer to Front Propeller Shaft Replacement in Propeller Shaft.

    7. Object Number: 662851 Size: SH
  7. Remove the motor/encoder electrical connector.

    8. Object Number: 647994 Size: SH
  8. Remove the electrical wiring harness from the transfer case.

    9. Object Number: 715667 Size: SH
  9. Remove the vent hose from the transfer case.
  10. Support the transmission with a suitable jack stand.

    11. Object Number: 647997 Size: SH
  11. Remove the transmission mount retaining bolts from the transmission support.

    12. Object Number: 680767 Size: SH
  12. Remove the transmission support mounting bolts from the frame.
  13. Remove the transmission support assembly. Refer to Transmission Support Replacement in Frame and Underbody.

    14. Object Number: 648001 Size: SH
  14. Remove the transmission mount from the transfer case adapter (automatic transmission only).

    15. Object Number: 648011 Size: SH
  15. Remove the transfer case to the transfer case adapter retaining nuts.

    16. Important: The following service procedure should be performed with the aid of another technician.

  16. Remove the transfer case from the transfer case adapter straight back toward the rear of the vehicle.
  17. Lower the front of the transfer case.
  18. Raise the rear of the transfer case so that it above the torsion bar bracket.
  19. In a downward motion, remove the transfer case from the vehicle.

    20. Object Number: 654219 Size: SH

    Important: If during the removal of the transfer case the gasket becomes damaged, do not reuse the gasket. Replace the damaged gasket with a new one. DO NOT use any type of sealant in place of the gasket.

  20. Remove the transfer case gasket.

Installation Procedure

    Object Number: 654219 Size: SH
  1. Install the new gasket to the transfer case adapter with the tab facing upward.

    2. Important: The following service procedure should be performed with the aid of another technician.

  2. Install the transfer case to the transfer case adapter.

    3. Object Number: 648011 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. Install the transfer case retaining nuts on the transfer case mounting studs.

    4. Tighten
    Tighten the transfer case retaining nuts to 55 N·m (40 lb ft).


    Object Number: 648001 Size: SH
  4. Install the transmission mount to the transfer case adapter.

    5. Tighten
    Tighten the transmission mount bolts to 47 N·m (35 lb ft).


    Object Number: 680767 Size: SH
  5. Install the transmission support assembly. Refer to Transmission Support Replacement in Frame and Underbody.

    6. Object Number: 647997 Size: SH
  6. Install the transmission mount retaining nuts.

    7. Tighten
    Tighten the transmission mount retaining nuts and bolts to 40 N·m (30 lb ft).

  7. Remove the transmission jack from the transmission.

    8. Object Number: 662851 Size: SH
  8. Install the motor/encoder electrical connector.

    9. Object Number: 647994 Size: SH
  9. Install the electrical wiring harness to the transfer case.

    10. Object Number: 715667 Size: SH
  10. Install the vent hose to the transfer case.

    11. Object Number: 648043 Size: SH
  11. Install the transfer case brace left side shown, if equipped.
  12. Install the transfer case brace bolts at the transfer case.

    13. Tighten
    Tighten the transfer case to engine bolts to 60 N·m (44 lb ft).

  13. Install the transfer case brace bolt at the engine.

    14. Tighten
    Tighten the transfer case brace bolt to 47 N·m (35 lb ft).

  14. Install the rear propeller shaft in the vehicle.
    15. • For vehicles equipped with the one piece propeller shaft, refer to One-Piece Propeller Shaft Replacement in Propeller Shaft.
    • For vehicles equipped with the two piece propeller shaft, refer to Two-Piece Propeller Shaft Replacement in Propeller Shaft.
  15. Install the front propeller shaft in the vehicle. Refer to Front Propeller Shaft Replacement in Propeller Shaft.
  16. Fill the transfer case with the approved fluid. Refer to Transfer Case Fluid Replacement .
  17. Install the transfer case shield to the vehicle. Refer to Transfer Case Shield Replacement .
  18. Lower the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.