What causes the torque convertor clutch to disengage?
There is a solenoid in your GM converter that causes the the torque convertor clutch (TCC) to engage and disengage. When the TCC solenoid receives a signal from the engine control module (ECM), it opens a passage in the valve body and hydraulic fluid applies the TCC.
What causes a GM torque converter to lock up?
Most of the time it is a stuck Torque Converter Clutch (TCC) solenoid, but this is not the only cause of this problem. General Motors has issued a few Technical Service Bulletins (TSBs) relating to this problem. There is also a specific diagnostic procedure to determine the exact cause of the TCC problem.
Can You unplug the solenoid on a GM converter?
Generally, if you unplug the TCC solenoid at the transmission and the symptoms go away, you have found the problem. But sometimes this can be misleading because you don’t know for sure if it’s a bad solenoid, dirt in the valve body or a bad signal from the ECM.
What happens to the solenoid on a torque converter?
When the ECM signal stops, the solenoid closes the valve and pressure is vented, causing the TCC to disengage. This lets the torque converter lock in “gear” or unlock out of “gear.”
What is the purpose of the torque converter clutch?
The purpose of the Transmission Converter Clutch (TCC) feature is to eliminate the power loss of the torque converter stage when the vehicle is in a cruise mode. The TCC System uses a solenoid-operated valve to couple the engine flywheel to the output shaft of the transmission through the torque converter.
Generally, if you unplug the TCC solenoid at the transmission and the symptoms go away, you have found the problem. But sometimes this can be misleading because you don’t know for sure if it’s a bad solenoid, dirt in the valve body or a bad signal from the ECM.
Most of the time it is a stuck Torque Converter Clutch (TCC) solenoid, but this is not the only cause of this problem. General Motors has issued a few Technical Service Bulletins (TSBs) relating to this problem. There is also a specific diagnostic procedure to determine the exact cause of the TCC problem.
What are the conditions for the converter clutch to apply?
For the converter clutch to apply, two conditions must be met: Internal transmission fluid pressure must be correct. The ECM must complete a ground circuit to energize the TCC solenoid that moves a check ball in the fluid line. This allows the converter clutch to apply when hydraulic pressure is correct.