Sable V6-3.0L VIN U (1999)
Torque Converter: Testing and Inspection
AX4N
Torque Converter Diagnosis
Prior to torque converter replacement all diagnostic procedures must be followed. This is to prevent the unnecessary replacement of good torque
converters. Only after a complete diagnostic evaluation can the decision be made to replace the 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
a. Perform the Torque Converter Clutch Operation Test.
4. Perform Diagnostic Procedures
a. Run On-Board Diagnostics.
(1) Repair all non-transmission related DTCs first.
(2) Repair all transmission DTCs.
(3) Rerun On-Board Diagnostics to verify repair.
b. Perform Line Pressure Test.
c. Perform Stall Speed Test.
d. Diagnosis by Symptom Routines.
(1) 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 control system and the torque converter are operating properly. Perform the test as follows:
1. Connect tachometer to engine.
2. Bring engine to normal operating temperature by driving vehicle at highway speeds for approximately 15 minutes in OD range.
3. After normal operating temperature is reached, maintain constant vehicle speed of about 80 km/h (50 mph) and tap brake pedal with the left foot.
4. 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
Torque Converter Operation Concerns in Diagnosis by Symptom Index.
