GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in the 4HI range only.

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

Incorrect fluid level or incorrect fluid

  1. Inspect the transfer case for the correct fluid level. Refer to Transfer Case Fluid Replacement .
  2. Inspect the transfer case for the correct type of fluid.
  3. Flush the transfer case and fill with the correct fluid, if required. Refer to Transfer Case Fluid Replacement .

Input gear thrust washers

  1. Inspect for worn or missing input gear thrust washers. Refer to Transfer Case Cleaning and Inspection.
  2. Replace the thrust washers, as required. Refer to Transfer Case Disassemble and Transfer Case Assemble.

2/4 Wheel drive synchronizer assembly

  1. Inspect the synchronizer for the following conditions:
  2. • The synchronizer hub internal teeth to rear output shaft splines for excessive looseness caused by wear
    • The synchronizer sleeve engagement teeth to the synchronizer gear for wear
  3. Replace the synchronizer assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble.

Rear output shaft bearing outer retaining ring

  1. Inspect for the following conditions:
  2. • Proper installation of the rear output shaft bearing retaining ring
    • Excessive wear or damaged retaining ring groove in the rear case half
  3. Repair or replace the following components if found faulty:
  4. • Properly install a new rear output shaft bearing outer retaining ring.
    • Replace the rear case half if the retaining ring groove is excessively worn. Refer to Transfer Case Disassemble and Transfer Case Assemble.

Worn high speed teeth on the range sleeve

  1. Inspect for worn high speed teeth on the range sleeve. Refer to Transfer Case Cleaning and Inspection.
  2. Replace the range sleeve if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble.