GM Service Manual Online
For 1990-2009 cars only

Strategy Based Diagnostics

Review the system operation in order to familiarize yourself with the system functions. Refer to Transfer Case Description and Operation.

Visual/Physical Inspection

    • Inspect the easily accessible or visible system components for obvious damage, or for conditions which could cause the symptom.
    • Inspect the transfer case for the proper fluid. Refer to Transfer Case Fluid Replacement.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

    •  No Correction for Slip in All-Wheel Drive Mode
    •  Service All-Wheel Drive Indicator Always On
    •  All-Wheel Drive Off Indicator Always On
    •  Transfer Case Popping Noise
    •  Transfer Case Whine or Rumble Noise
    •  Transfer Case Clunk During Acceleration and Deceleration
    •  Transfer Case Leak Diagnosis