In listed Ford and GM transmissions, the TCC regulator valve controls the application and release of the torque converter. The boost valve and sleeve assembly receive signal fluid that forces the valve to shuttle to its regulating position. In this position, the torque converter apply circuit is open to the secondary line and the torque converter release circuit is vented. This moves the converter into lockup state. Once the signal fluid is removed from the circuit, the TCC regulator valve returns to its install position where the torque converter apply circuit is disconnected from the secondary line and the torque converter release circuit is pressurized. This returns the converter to its released state.

The OE valve spring is subject to breakage or fatigue failure and can prevent proper release of the converter clutch. Correcting these concerns would normally require replacing the valve body. Installing Sonnax TCC regulator valve spring 105740-29 restores proper control of the valve.

• Replacement spring maintains OE functions and pressures
• Manufactured from upgraded material to increase spring strength and resiliency