GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 Cobalt 🢒 Transmission 🢒 Automatic Transmission - 4T45-E 🢒 Symptoms - Automatic Transmission

Diagnostic Category

Diagnostic Information

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
    • Line pressure - high or low
    • Fluid leaks
    • Refer to Transmission Fluid Check .
    • Refer to Fluid Foaming .
    • Refer to High or Low Line Pressure .
    • Refer to Fluid Leak Diagnosis .
    • Refer to Automatic Transmission Fluid Leaks .

Noise and Vibration Diagnosis

This category contains the following topics:

    • Ratcheting noise
    • Noise - drive gear, final drive, whine, growl, rattle, buzz, popping
    • Vibration
    • Refer to Ratcheting Noise .
    • Refer to Whine Noise Varying with RPM .
    • Refer to High Pitch Whine Noise .
    • Refer to Popping Noise .
    • Refer to Final Drive Noise or Hum Noise .
    • Refer to Noise in Random Ranges .
    • Refer to Noise and Vibration Analysis .
    • Refer to Vibration .

Range Performance Diagnosis

This category contains the following topics:

    • Drives in Neutral
    • No Park
    • No Reverse
    • No Drive
    • Loss of power
    • No engine braking
    • Shift indicator indicating wrong gear
    • No gear selection
    • Refer to Drives in Neutral .
    • Refer to No Park .
    • Refer to No Reverse or Slips in Reverse .
    • Refer to Loss of Drive .
    • Refer to Loss of Power .
    • Refer to Engine Stall .
    • Refer to No Engine Braking; All Manual Ranges .
    • Refer to No Gear Selection .

Shift Quality - Feel - Diagnosis

This category contains the following topic:

Harsh shifts

Refer to Harsh Shifts .

Shift Pattern

This category contains the following topics:

    • One forward gear only
    • Specific forward gears only
    • Slipping
    • Refer to Second Gear Only .
    • Refer to First and Second Gears Only .
    • Refer to First and Fourth Gears Only .
    • Refer to Second and Third Gears Only .
    • Refer to Third and Fourth Gears Only .
    • Refer to No First Gear, Slips in First Gear .
    • Refer to No Second Gear, Slips in Second Gear .
    • Refer to No Third Gear, Slips in Third Gear .

Shift Speed Diagnosis

This category contains the following topic:

Inaccurate or inconsistent shift points

Refer to Inaccurate/Inconsistent Shift Points .

Torque Converter Diagnosis

This category contains the following topics:

    • Torque converter diagnosis
    • TCC remains engaged
    • TCC application while engine is cold
    • TCC shudder
    • Engine stalling
    • Refer to Torque Converter Diagnosis .
    • Refer to No Torque Converter Clutch Release .
    • Refer to Torque Converter Clutch Shudder .
    • Refer to Engine Stall .

If no symptoms are found:
    • Refer to Transmission Fluid Check .
    • Refer to Road Test .
    • Refer to Line Pressure Check .