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 Rear Axle Disassembled Views and Rear Drive Axle Description and Operation and Wheel Drive Shafts Description and Operation . 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 condition. The diagnostic flow is the place to start when repairs are necessary. For a detailed explanation, refer to Strategy Based Diagnosis .

Visual/Physical Inspection

    • Inspect for aftermarket devices, which could affect the operation of the vehicle. Refer to Checking Aftermarket Accessories .
    • Inspect the easily accessible or visible system components for obvious damage or conditions, which could cause the symptom.
    • Inspect for the correct lubricant level and the proper viscosity.
    • 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
    •  Diagnostic Starting Point - Automatic Transmission for the 6L50/6L80/6L90 transmission
    •  Transmission Noisy for the Tremec 6-Speed transmission
    •  Symptoms - Propeller Shaft
    •  Clutch Noisy
    •  Noisy in Drive
    •  Noisy When Coasting
    •  Intermittent Noise
    •  Constant Noise
    •  Noisy on Turns
    •  Rear Axle Lubricant Leak Diagnosis