GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Uplander Ext. 🢒 General Information 🢒 Vibration Diagnosis and Correction 🢒 Symptoms - Automatic Transmission

Diagnostic Category

Diagnostic Information

DEFINITION: This table consists of eight 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
    • Line pressure - high or low
    • Fluid leaks
    • Refer to Transmission Fluid Check .
    • Refer to Incorrect Line Pressure .
    • Refer to Automatic Transmission Fluid Leaks .
    • Refer to Fluid Leak Diagnosis .

Noise and Vibration Diagnosis

This category contains the following topics:

    • Noise - drive gear, final drive, whine, growl, hum, rattle, buzz, popping
    • Torque converter diagnosis
    • Noise and vibration analysis
    • Refer to Popping Noise .
    • Refer to Final Drive Noise or Hum Noise .
    • Refer to Noise in Random Ranges .
    • Refer to Torque Converter Diagnosis .
    • Refer to Noise and Vibration Analysis .

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 No Park Range .
    • Refer to Slips in Reverse or No Reverse .
    • Refer to Slips in Drive or No Drive .
    • Refer to Locked Up in Drive/Reverse .

Shift Quality (Feel) Diagnosis

This category contains the following topics:

    • Harsh shifts
    • Soft shifts
    • Harsh engagement, garage shifts
    • Delayed engagement, garage shifts
    • Refer to Harsh or Soft 1-2 Shift Feel .
    • Refer to Harsh or Soft 2-3/3-2 Shift Feel .
    • Refer to Harsh or Soft 3-4/4-3 Shift Feel .

Slipping or Missing Gears

This category contains the following topics:

    • No upshift
    • Slipping or missing gears
    • One forward gear only
    • Two forward gears only
    • Non-First gear start
    • Refer to Slipping or No First Gear .
    • Refer to Slipping or No Second Gear .
    • Refer to Slipping or No Third Gear .
    • Refer to Slipping or No Fourth Gear .
    • Refer to First Gear Only .
    • Refer to Second Gear Only .
    • Refer to Third Gear Only .
    • Refer to Fourth Gear Only .

Shift Speed Diagnosis

This category contains the following topic:

Incorrect shift points

Refer to High or Low Upshift or Downshift Speed .

Torque Converter Diagnosis

This category contains the following topics:

    • Torque converter diagnosis
    • TCC does not apply
    • TCC does not release
    • TCC shudder
    • Refer to Torque Converter Diagnosis .
    • Refer to No Torque Converter Clutch Apply .

Symptom Can Not Be Duplicated or Symptom Not Found

This category contains the following topics:

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