Torque Converter Diagnosis

6F50

Torque Converter Diagnosis

Prior to torque converter installation, 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's concern

3. Verify the concern - carry out the Torque Converter Clutch (TCC) Operation Test.

4. Carry out diagnostic procedures:
- Run On-Board Diagnostic (OBD). Refer to Diagnostics Diagnostics.
- Repair all non-transmission related DTCs first.

- Repair all transmission DTCs.

- Rerun OBD to verify repair.

- Carry out Line Pressure Test Line Pressure Test. Refer to Special Testing Procedures Special Testing Procedures.

- Carry out Stall Speed Test Stall Speed Test. Refer to Special Testing Procedures Special Testing Procedures.

- Carry out diagnostic routines Diagnostic Routines. 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 repair as required, before installing a new torque converter.


Torque Converter Clutch (TCC) Operation Test

This test verifies that the TCC control system and the torque converter are operating correctly.

1. Carry out Self Test, refer to the tester manual. Check for DTCs.

2. Connect a tachometer to the engine.

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

4. If the vehicle stalls in (D) at idle with vehicle at a stop, move the selector lever to manual L position. If the vehicle stalls, see torque converter operation concerns, refer to Diagnosis By Symptom Diagnosis By Symptom. Repair as required. If the vehicle does not stall in (D), refer to Diagnosis By Symptom Diagnosis By Symptom.