GM Service Manual Online
For 1990-2009 cars only

Symptoms - Automatic Transmission

Diagnostic Category

Diagnostic Information

The following table consists of nine 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 diagnostics information.

Fluid Diagnosis

This category contains the following topics:

    • Fluid condition - appearance, contaminants, smell, overheating
    • Line pressure - high or low
    • Fluid leaks
    • Refer to Transmission Fluid Check .
    • Refer to Line Pressure Check .
    • Refer to Engine Coolant/Water in Transmission .
    • Refer to Fluid Leak Diagnosis .
    • Refer to Transmission Overheats .
    • Refer to Automatic Transmission Fluid Leaks .

Noise and Vibration Diagnosis

This category contains the following topics:

    • Noise - drive gear, final drive, whine, growl, hum, rattle, knock, clunk
    • Vibration
    • Refer to Noise and Vibration Analysis .
    • Refer to Vibration at Idle .
    • Refer to Vibration While Driving .
    • Refer to Hum or Rattle Noise at Idle .

Range Performance Diagnosis

This category contains the following topics:

    • No Park
    • No Reverse or slips
    • No Drive or slips
    • No engine braking
    • Range selector displays incorrect range
    • Refer to Stall Speed Test .
    • Refer to Engagement Delay Test .
    • Refer to No Forward and Reverse .
    • Refer to Slips in Drive or No Drive .
    • Refer to Slips in Reverse or No Reverse .
    • Refer to Slips on Acceleration .
    • Refer to No Engine Braking in Fourth Gear .
    • Refer to No Engine Braking in Third Gear .
    • Refer to No Engine Braking in Second Gear .

Shift Quality Feel Diagnosis

This category contains the following topics:

    • Harsh shifts
    • Soft shifts
    • Harsh engagement
    • Delayed engagement
    • Refer to Harsh Upshift .
    • Refer to Harsh Shift on Coastdown .
    • Refer to Harsh Forced Downshift .

Shift Pattern

This category contains the following topics:

    • No upshift
    • No downshift
    • Refer to No 1-2 Upshift .
    • Refer to No 2-3 Upshift .
    • Refer to No 3-4 Upshift .
    • Refer to No 4-5 Upshift .
    • Refer to No 5-4 Downshift .
    • Refer to No 4-3 Downshift .
    • Refer to No 3-2 Downshift .
    • Refer to No 2-1 Downshift .

Shift Speed Diagnosis

This category consists of the following topic:

Inaccurate or inconsistent shift points

Torque Converter Diagnosis

This category contains the following topics:

    • Torque converter diagnosis
    • TCC does not apply
    • TCC does not release
    • TCC apply/release quality
    • Refer to Torque Converter Diagnosis .

Symptom Can Not Be Duplicated or Symptom Not Found

This category contains the following topics:

    • Transmission fluid diagnosis
    • Line pressure diagnosis
    • Road testing
    • Refer to Transmission Fluid Check .
    • Refer to Line Pressure Check .
    • Refer to Road Test .