GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Sierra Classic - 4WD 🢒 Preface 🢒 Cautions and Notices 🢒 Transfer Case Assembly Replacement

Removal Procedure

    Object Number: 860643 Size: SH
  1. Remove the transfer case shield, if equipped. Refer to Transfer Case Shield Replacement.
  2. Remove the front propeller shaft. Refer to Front Propeller Shaft Replacement.
  3. Remove the rear propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement.
  4. Remove the in-line to engine harness electrical connector (1) from the bracket.
  5. Disconnect the gear indicator switch electrical connector (2).
  6. Disconnect the speed sensor electrical connector (4).
  7. Remove the harness clips (3) from the transfer case.
  8. Reposition the harness.

    9. Object Number: 715667 Size: SH
  9. Remove the vent hose.
  10. Remove the control rod. Refer to Transfer Case Control Rod Replacement.
  11. Support the transmission with a suitable transmission jack stand.

    12. Object Number: 647997 Size: SH
  12. Remove the transmission mount nuts.
  13. Raise the transmission slightly in order to remove the transmission support

    14. Object Number: 652595 Size: SH
  14. Remove the transmission support bolts.
  15. Remove the transmission support.
  16. Support the transfer case with a suitable jack stand.

    17. Object Number: 715661 Size: SH
  17. Remove the transmission mount bolts.

    18. Object Number: 648001 Size: SH
  18. Remove the transmission mount.

    19. Object Number: 715663 Size: SH
  19. Remove the transfer case adapter nuts.

    20. Object Number: 828574 Size: SH
  20. Remove the shift control switch harness bracket.

    21. Important: The following service procedure must be performed with the assistance from another technician.

  21. Separate the transfer case from the transmission by moving the transfer case straight back toward the rear of the vehicle.
  22. Rotate the transfer case so that the front output shaft is above the torsion bar bracket.
  23. Rotate the transfer case (with the input shaft slightly lowered) so that the transfer case is parallel to the torsion bar bracket.
  24. Lower the transfer case.

Installation Procedure
  1. Apply GM /P/N 12345879 (Canadian P/N 10953511) or equivalent lubricant meeting GM Specification 9985830 to the input shaft splines.

    2. Object Number: 828574 Size: SH

    Important: The following installation procedure must be performed with the assistance of another technician.

  2. Raise the transfer case into position (the transfer case should be parallel to the torsion bar bracket).
  3. Rotate the transfer case so that it is in line with the adapter.
  4. Install the transfer case.
  5. Install the shift control switch harness bracket.

    6. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 715663 Size: SH
  6. Install the transfer case adapter nuts.

    7. Tighten
    Tighten the nuts to 50 N·m (37 lb ft).


    Object Number: 648001 Size: SH
  7. Install the transmission mount.

    8. Object Number: 715661 Size: SH
  8. Install the transmission mount bolts.

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


    Object Number: 652595 Size: SH
  9. Install the crossmember.
  10. Install the crossmember bolts.

    11. Tighten
    Tighten the bolts to 70 N·m (52 lb ft).


    Object Number: 647997 Size: SH
  11. Lower the transfer case and transmission onto the transmission support.
  12. Install the transmission mount nuts.

    13. Tighten
    Tighten the nuts to 40 N·m (30 lb ft).

  13. Remove the support from the transfer case.
  14. Remove the transmission jack stand.
  15. Install the control rod. Refer to Transfer Case Control Rod Replacement.

    16. Object Number: 715667 Size: SH
  16. Install the vent hose.

    17. Object Number: 860643 Size: SH
  17. Position the harness.
  18. Install the harness clips (3) to the transfer case.
  19. Connect the speed sensor electrical connector (4).
  20. Connect the gear indicator switch electrical connector (2).
  21. Install the in-line to engine harness electrical connector (1) to the bracket.
  22. Install the rear propeller shaft. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement.
  23. Install the front propeller shaft. Refer to Front Propeller Shaft Replacement.
  24. Check the fluid level. Add fluid if necessary.
  25. Install the transfer case shield, if equipped. Refer to Transfer Case Speed Sensor Replacement.