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 4LO range only.

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

High/low planetary carrier assembly

  1. Inspect for the following conditions:
  2. • Excessively worn planetary gears
    • The planetary gears loose in the planetary carrier
    • Excessively worn high/low clutch engagement teeth on the carrier
  3. Replace the high/low planetary if any of the above conditions are found.

Refer to Transfer Case Disassemble and Transfer Case Assemble .

High/low internal gear

  1. Inspect the high/low internal gear to front case fit for excessive looseness.
  2. Replace the front case half if the high/low internal gear is loose. Refer to Transfer Case Disassemble and Transfer Case Assemble .

High/low clutch

  1. Inspect the high/low clutch engagement teeth for excessive wear.
  2. Inspect the high/low clutch to rear output shaft splines for excessive wear.
  3. Replace the high/low clutch if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble .