GM Service Manual Online
For 1990-2009 cars only

Diagnostic Category

Diagnostic Information

DEFINITION: The following table consists of seven diagnostic categories that are located in the left-hand column. Using this column, choose the appropriate category based on the operating conditions of the vehicle or transmission. After selecting a category, use the right-hand column to locate the specific symptom diagnostic information.

Fluid Diagnosis

This category contains the following topics:

    • Fluid condition - appearance, contaminants, smell, overheating
    • Fluid leaks
    • Refer to Engine Coolant/Water in Transmission .
    • Refer to Fluid Leak Diagnosis .

Noise and Vibration Diagnosis

This category contains the following topics:

    • Noise - drive gear, final drive, whine, growl, rattle, buzz, popping
    • Vibration

Refer to Torque Converter Diagnosis .

Range Performance Diagnosis

This category contains the following topics:

    • No Park
    • No engine braking
    • Refer to No Park .
    • Refer to No Engine Braking in First Gear .

Shift Quality/Feel Diagnosis

This category contains the following topic:

Harsh shifts

Refer to Harsh Park or Neutral to Drive Engagement .

Torque Converter Diagnosis

This category contains the following topic

Torque Converter Diagnosis

Refer to Torque Converter Diagnosis .

If no symptoms are found

    • Refer to Transmission Fluid Check .
    • Refer to Road Test .