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:

    â€¢ Fluid condition - appearance, contaminants, smell, overheating
    â€¢ Line pressure - high or low
    â€¢ Fluid leaks
    â€¢ Refer to Transmission Fluid Check .
    â€¢ Refer to Line Pressure Check .
    â€¢ Refer to Fluid Leak Diagnosis .

Noise and Vibration Diagnosis

This category contains the following topics:

    â€¢ Noise - drive gear, final drive, whine, growl, rattle, buzz, popping
    â€¢ Vibration

Refer to Flex Plate/Torque Converter Vibration Test .

Range Performance Diagnosis

This category contains the following topics:

    â€¢ No Park
    â€¢ No Reverse
    â€¢ No Drive
    â€¢ No engine braking
    â€¢ No gear selection
    â€¢ Refer to Vehicle does Not Hold in P Range .
    â€¢ Refer to Unable to Run in All Ranges .
    â€¢ Refer to No Engine Braking in 2 or L Range .
    â€¢ Refer to Range Selector Lever Cable Replacement .

Shift Quality/Feel Diagnosis

This category contains the following topic:

Harsh shifts

Refer to Harsh Engagement into any Drive Range .

Shift Pattern

This category contains the following topics:

    â€¢ One forward gear only
    â€¢ Slipping
    â€¢ Refer to Fluid Discolored or Smells Burnt .
    â€¢ Refer to Harsh Downshift .

Torque Converter Diagnosis

This category contains the following topic

Torque Converter Diagnosis

Refer to Flex Plate/Torque Converter Vibration Test .

If no symptoms are found

    â€¢ Refer to Transmission Fluid Check .
    â€¢ Refer to Road Test .
    â€¢ Refer to Line Pressure Check .