GM Service Manual Online
For 1990-2009 cars only

Transfer Case Cleaning and Inspection Cleaning and Inspection

  1. Clean the bearings.
  2. Remove all old lubricant and dirt.

  3. Clean the shafts.
  4. Clean the sprockets.
  5. Clean the chain.
  6. Clean the oil feed ports and the channels in each case half.
  7. Apply compressed air to each oil feed port and channel and channel in order to remove any obstructions or cleaning solvent residue.

  8. Clean all mating and sealing surfaces.
  9. Inspect the bearings and the thrust washers for the following conditions:
  10. • Spalling
    • Brinneling
    • Corrosion
  11. Inspect the gear teeth for the following conditions:
  12. • Excessive wear or damage
    • Spalling
    • Cracks
    • Corrosion
  13. Inspect the gear splines for the following conditions:
  14. • Excessive wear
    • Spalling
    • Cracks
    • Twist
    • Corrosion
  15. Inspect the shaft splines for the following conditions:
  16. • Excessive wear
    • Spalling
    • Cracks
    • Distortion
    • Corrosion
  17. Inspect the retainer rings for the following conditions:
  18. • Excessive wear
    • Distortion
    • Damage
  19. Inspect the case halves for the following conditions:
  20. • Damaged or warped mating surfaces
    • Cracks
    • Porosity
    • Damaged thread holes
  21. Inspect the synchronizer stop rings for the following conditions:
  22. • Cracks
    • Chips
    • Spalling
    • Excessive wear
  23. Inspect the synchronizer hub and sleeve for the following conditions:
  24. • Cracks
    • Chips
    • Spalling
    • Excessive wear
  25. Inspect the pads on the mode fork and on the range fork for the following conditions:
  26. • Wear
    • Distortion
  27. Inspect the oil pump gears and the case halves for the following conditions:
  28. • Wear
    • (Replace the complete assembly if there is excessive wear.)
    • Spalling
    • Cracks
    • Damage
  29. Inspect the following components for excessive wear:
  30. • The input gear
    • The planetary carrier
    • The range shift hub tooth chamfers