GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: A faulty internal transfer case component that causes a growl or grinding noise in the transfer case while the vehicle is turning.

Review the Symptoms - Transfer Case and perform the necessary inspections.

Planetary differential

  1. Inspect the planetary differential pinion gears for the following conditions:
  2. • Chipped, bent, or deformed teeth
    • Pinion gear bushings worn
    • Pinion gear thrust washers missing
    • Seized or binding pinion gears
  3. Inspect the planetary differential for deformation. Refer to Transfer Case Cleaning and Inspection.
  4. Replace the planetary differential assembly, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble.

Sun gears

  1. Inspect the sun gears for the following conditions:
  2. • Gear tooth failure
    • Worn or galled thrust surfaces
  3. Replace the sun gears, if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble.

Thrust washer

  1. Inspect the thrust washer for seizure to the planetary differential.
  2. Inspect the thrust washer for galling.
  3. Replace the thrust washer, if faulty, and the mating component, if damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble.

Planetary differential not timed properly

  1. Inspect the planetary differential for being timed properly. Refer to Transfer Case Assemble.
  2. Properly time the planetary differential gears. Refer to Transfer Case Assemble.