Torque Converter Clutch: Description and Operation

Torque Converter Clutch

When a pre-determined speed is achieved in fourth gear, the torque converter clutch is enabled by the transmission control module through the pulse width modulated solenoid and a clutch plate provides a direct drive so reducing fuel consumption. Pulsing the solenoid causes the TCC valve to modulate pressure against the TCC. This pulsing or modulated pressure allows the TCC to slip slightly so providing a smooth apply and release of the TCC.

If the transmission fluid exceeds a temperature of 1250°C the TCC will also apply in second and third gears to reduce friction generated in the torque converter.


Pulse Width Modulated (PWM) Solenoid

This solenoid provides the gradual apply and release of the torque converter clutch for increased shift quality, see TCC.


Torque Converter Clutch Enable Valve

To retain the TCC in a released condition, the TCC shift valve is held by regulated converter feed fluid which passes through the enable valve to the TCC enable circuit.


Torque Converter Clutch Shift Valve

The TCC shift valve, being held in the release position by spring force and TCC enable fluid, permits regulated converter feed fluid to pass through the valve and enter the TCC release circuit. To apply the TCC, enable fluid exhausts and the valve is shifted by signal fluid pressure


Converter Limiting Valve

This valve permits converter feed pressure from the pressure regulator valve to enter the regulated converter feed circuit. Excess converter feed pressure causes the limit valve to move against its spring pressure, and so the converter feed fluid is opened to exhaust.