Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnosis - Torque Converter Clutch: Description: Notes
The torque converter clutch assembly consists of a 3-element torque converter with the addition of a converter clutch. The converter clutch is an internal mechanism with friction material attached to the front face. It is splined to the turbine assembly in the converter. When in operation, the clutch applies against the converter cover, providing a mechanical direct drive coupling of the engine to the transmission planetary gear. Applying the converter clutch eliminates converter slippage, resulting in improved fuel economy and reduced fluid operating temperatures. When the converter clutch is released, the assembly operates as a conventional torque converter.
Converter clutch apply and release is controlled by several factors. On 4WD vehicles one of these is drive range selection. When transfer case is shifted from 2H to 4L or 4H, circuit TCC system is opened. In this position (4L or 4H) converter clutch will not apply. When transfer case is shifted back to 2H, TCC system operates in normal manner. If vehicle does not shift out of 4L or 4H, converter clutch will not apply.
Converter clutch apply and release is controlled by the position of the converter clutch apply valve, located in oil pump on THM 180C and 200C, valve body on THM 200-4R, 325-4L and 700-R4, and in auxiliary valve body on THM 125C, 250C and 350C. Apply valve operation is controlled by a solenoid.
In order for the torque converter clutch to engage, the transmission must by operating in 3rd gear (3rd or 4th on 4-speed models) and vehicle speed must be over a specific level (typically 30-35 MPH). In addition, several other controls may be incorporated in the vacuum/electrical system to aid in the apply and release of the converter clutch. Specific additional component use is determined by whether or not the vehicle is equipped with Computer Command Control (CCC) system, and some other factors. On vehicle with the CCC system, operation of the apply solenoid is controlled by the Electronic Control Module (ECM). On system without CCC, the solenoid control signal is routed through whatever additional control are used, any of which may break the circuit if specific operating conditions are not met. These controls are external to the transmission and operated as described.
The following components supply engine condition information to the ECM on CCC equipped vehicles:
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.