GM Service Manual Online
For 1990-2009 cars only

Diagnostic Category

Diagnostic Information

This 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
    â€¢ Refer to High or Low Line Pressure
    â€¢ Refer to Fluid Foaming

Noise and Vibration Diagnosis

This category contains the following topics:

    â€¢ Noise in drive gears
    â€¢ Noises (whine, growl, rattle, buzz, popping)
    â€¢ Vibration
    â€¢ Refer to Noise in All Ranges
    â€¢ Refer to Noise in First or Reverse Gear
    â€¢ Refer to Noise in Second
    â€¢ Refer to Chatters/Slips in First Gear

Range Performance Diagnosis

This category contains the following topics:

    â€¢ No Reverse
    â€¢ No Drive
    â€¢ Loss of power
    â€¢ No engine braking
    â€¢ Refer to No Gear Selection
    â€¢ Refer to Slips in Reverse or No Reverse
    â€¢ Refer to No Drive in Drive or Intermediate Range
    â€¢ Refer to No Drive in Forward Ranges
    â€¢ Refer to No Drive in All Ranges
    â€¢ Refer to No Drive in Drive Range
    â€¢ Refer to No Overrun Braking in Low

Shift Quality (Feel) Diagnosis

This category contains the following topic:

    â€¢ Harsh shifts
    â€¢ Soft (slipping) shifts
    â€¢ Delayed engagement
    â€¢ Refer to Slipping or Harsh 1-2 Shift
    â€¢ Refer to 2-3 Shift Rough or Delay
    â€¢ Refer to 2-3 Shift Soft, Slips, or Early
    â€¢ Refer to Delay in Drive and Reverse

Shift Pattern

This category contains the following topics:

    â€¢ No upshift
    â€¢ No downshift
    â€¢ Missed or shift slipping
    â€¢ Non-first gear starts
    â€¢ Refer to No 2-3 Shift or 2-3 Shift Delay
    â€¢ Refer to No Intermediate Range
    â€¢ Refer to Binds in Third Gear
    â€¢ Refer to Chatters/Slips in First Gear
    â€¢ Refer to No Full Throttle Downshift
    â€¢ Refer to Shifts 1-3, Misses Second Gear
    â€¢ Refer to Second Speed Start

Shift Speed Diagnosis

This category contains the following topic:

Inaccurate or inconsistent shift points

Refer to No 2-3 Shift or 2-3 Shift Delay

Torque Converter Diagnosis

This category contains the following topics:

    â€¢ Torque converter diagnosis
    â€¢ TCC remains engaged (engine stalling)
    â€¢ Refer to Torque Converter Diagnosis

If No Symptom Found

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