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.

High/low planetary carrier assembly

  1. Inspect the high/low planetary carrier pinion gears for the following conditions:
  2. • Chipped, bent or deformed teeth
    • Pinion gear needle bearing worn
    • Pinion gear thrust washers missing
    • Seized or binding pinion gears
  3. Inspect the high/low planetary carrier input gear for excessive thrust end play.
  4. Inspect the input gear teeth for excessive wear or damage.
  5. Replace the high/low planetary carrier assembly if any of the above conditions exist. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Ring gear

  1. Inspect the ring gear for teeth damage or wear. Refer to Transfer Case Cleaning and Inspection .
  2. Replace the ring gear if it is faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

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 it is 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 they are faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Thrust washers

  1. Inspect the thrust washers for seizure to the planetary differential.
  2. Inspect the thrust washers for galling.
  3. Replace the thrust washers if they are faulty and the mating component if it is 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 .