Component Tests

Torque Converter Diagnosis
Prior to torque converter replacement, 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 new or remanufactured torque converters.

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 Operation Test.
4. Carry out Diagnostic Procedures.
^ Run on-board diagnostics. Refer to On-Board Diagnostics with diagnostic tool Displaying & Reading Trouble Codes
Repair all non-transmission-related DTC's first.
Repair all transmission DTC's.
Rerun on-board diagnostics to verify repair.
^ Carry out Line Pressure Test. Line Pressure Test
^ Carry out Stall Speed. Stall Speed Test
^ Carry out Diagnostic Routines. Diagnosis by Symptom Chart Directions
Use the Diagnosis by Symptom 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 repairing the torque converter. Displaying & Reading Trouble Codes

Torque Converter Operation Test
This test verifies that the torque converter clutch control system and the torque converter are operating correctly.
1. Carry out Quick Test, refer to On-Board Diagnostics with diagnostic tool. Check for DTC's. Refer to the Diagnostic Trouble Code Chart. Clearing Trouble Codes TorqShift Automatic Transmission
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. 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 brake pedal is tapped and decrease about five seconds after pedal is released. If this does not occur, refer to Diagnosis By Symptom-Torque Converter Clutch Operation Concerns. Torque Converter Clutch Operation Concerns, 250-253