GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: The transfer case is not delivering engine torque to the front propeller shaft.

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

Viscous coupling faulty

  1. Inspect the transfer case fluid for being black. If the fluid is black, it is most likely caused by a viscous coupling failure.
  2. Test for a faulty viscous coupling. Refer to Transfer Case Viscous Coupling Test .
  3. Disassemble the transfer case. Refer to Transfer Case Disassemble.
  4. Inspect the viscous coupling for leaking. Refer to Transfer Case Cleaning and Inspection.
  5. Replace the viscous coupling if it is faulty. Refer to Transfer Case Assemble.

Planetary carrier faulty

  1. Disassemble the transfer case. Refer to Transfer Case Disassemble.
  2. Inspect for faulty planetary carrier components. Refer to Transfer Case Cleaning and Inspection.
  3. Replace any faulty planetary carrier components. Refer to Transfer Case Assemble.