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 or in a four wheel drive mode.

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

High/low planetary carrier assembly

  1. Inspect the high/low planetary carrier assembly for the following conditions:
  2. • Chipped, bent, or deformed teeth
    • Planetary gear needle bearings worn
    • Planetary gear thrust washers cracked or missing
    • Seized or binding planetary gears
  3. Replace the high/low planetary carrier assembly if any of the above conditions exist. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Input shaft

  1. Inspect the input shaft in the planetary carrier assembly for excessive thrust end play.
  2. Inspect the input shaft teeth for the following conditions:
  3. • Damage
    • Worn or galled thrust surfaces
    • Excessive wear
    • Chipped teeth
    • Metal embedded in the root of the teeth
  4. Replace the input shaft if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .

Thrust washers

  1. Inspect for missing or damaged thrust washers for the input shaft.
  2. Inspect the thrust washers for galling.
  3. Replace the thrust washers if faulty and the mating component if damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble .

High/low internal gear

  1. Inspect the high/low internal gear teeth for the following conditions:
  2. • Damage
    • Chipped teeth
    • Excessive wear
    • Metal embedded in the root of the teeth
  3. Replace the front case half if the high/low internal gear is faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .