GM Service Manual Online
For 1990-2009 cars only

Cause

Action

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

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

Input shaft thrust washers

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

Rear output shaft rear bearing outer retaining ring

  1. Inspect for the following conditions:
  2. • Properly installed rear output shaft rear bearing outer 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 rear 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 high/low clutch

  1. Inspect for worn high speed teeth on the high/low clutch. Refer to High/Low Shift Components Cleaning and Inspection .
  2. Replace the high/low clutch if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble .