Torque Converter Diagnosis

5R44E and 5R55E

Torque Converter Diagnosis

NOTE: Always drive the vehicle in a safe manner according to driving conditions and obey all traffic laws.

Prior to installing new or remanufactured torque converters, all diagnostic procedures must be followed. This is to prevent the unnecessary installation of new or remanufactured torque converters. Only after a complete diagnostic evaluation can the decision be made to install a new or remanufactured torque converter.

Begin with the normal diagnostic procedures as follows:

1. Preliminary Inspection.

2. Know and Understand the Customer Concern.

3. Verify the Concern. Refer to the Torque Converter Operation Test.

4. Carry out Diagnostic Procedures.

- Run the On-Board Diagnostic (OBD) test. Refer to On-Board Diagnostic (OBD) With Scan Tool. Diagnostics
- Repair all non-transmission related DTCs first.
- Repair all transmission DTCs.
- Rerun OBD test to verify repair.

- Carry out Line Pressure Test. Refer to the Special Testing Procedures Special Testing Procedures. Line Pressure Test
- Carry out Stall Speed Test. Refer to the Special Testing Procedures Special Testing Procedures. Stall Speed Test
- Carry out Diagnosis by Symptom Index. Refer to Diagnosis By Symptom Diagnosis By Symptom.
- Use the index to locate the appropriate routine that best describes the symptom(s). The routine will list all possible components that may cause or contribute to the symptom. Check each component listed; diagnose and service as required before servicing the torque converter.


Torque Converter Operation Test

This test verifies that the Torque Converter Clutch (TCC) control system and the torque converter are operating correctly.

1. Carry out Self Test. Refer to On-Board Diagnostic (OBD) With Scan Tool. Check for DTCs. Refer to the DTC Chart. Diagnostics Diagnostic Trouble Code Tests and Associated Procedures

2. Connect a scan tool and monitor engine rpm.

3. Bring the engine up to normal operating temperature by driving the vehicle at highway speeds for approximately 15 minutes with the selector lever in the (D) position.

4. After normal operating temperature is reached, maintain a constant vehicle speed of about 80 km/h (50 mph) and tap brake pedal with the left foot.

5. Engine rpm should increase when the brake pedal is tapped, and decrease about 5 seconds after the pedal is released. If this does not occur, refer to the Torque Converter Clutch (TCC) Operation Concerns in Diagnosis By Symptom Diagnosis By Symptom.

6. If the engine stalls in (D) or manual 2 at idle with the vehicle stopped, move the selector lever to the manual 1 position. If the engine stalls, refer to the Torque Converter Clutch (TCC) Operation Concerns in Diagnosis By Symptom Diagnosis By Symptom. Repair as required. If the engine does not stall in (D), refer to Diagnosis By Symptom Diagnosis By Symptom.