GM Service Manual Online
For 1990-2009 cars only

Strategy Based Diagnostics

Review the system operations in order to familiarize yourself with the system functions. Refer to Transfer Case Description and Operation in Transfer Case - Vibe, and Differential Carrier Assembly Description in Rear Drive Axle. All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system problem. The diagnostic flow is the place to start when repairs are necessary.

Visual/Physical Inspection

    • Inspect the easily accessible or visible system components for obvious damage or conditions, which could cause the symptom.
    • Check for the correct lubricant levels and the proper viscosities.
    • Verify the exact operating conditions under which the concern exists. Note factors such as vehicle speed, road conditions, ambient temperature, and other specifics.
    • Compare the driving characteristics or sounds, if applicable, to a known good vehicle and make sure you are not trying to correct a normal condition.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.

Symptom List

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

    •  Diagnostic Starting Point - Vibration Diagnosis and Correction in Vibration Diagnosis and Correction
    •  Diagnostic Starting Point - Transfer Case
    •  Diagnostic Starting Point - Rear Differential Carrier in Rear Drive Axle
    •  Transfer Case Leak Diagnosis