Torque Converter Diagnosis

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.

NOTE: If equipped, turn the power take-off unit off for correct test results. For a description of PTO operation, refer to Transmission Electronic Control System. Transmission Electronic Control System

During PTO operation, the on-board diagnostics will be disabled. However, the circuit checks made by the diagnostic system and the FMEM will continue. The PTO must be turned off to do on-board diagnostics.
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. Torque Converter Operation Test
4. Carry out Diagnostic Procedures.
^ Run on-board diagnostics. Refer to On-Board Diagnostics with scan tool. On-Board Diagnostics With Scan Tool
^ Repair all non-transmission-related DTCs first.
^ Repair all transmission DTCs.
^ Rerun on-board diagnostics to verify repair.
^ Carry out Line Pressure Test. Line Pressure Test
^ Carry out Stall Speed Test. Stall Speed Test
^ Carry out Diagnostic Routines.
^ 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.