In GM Gen. 1 10L60, 10L80 and 10L90 transmissions, the TCC regulator valve controls the application and release of the torque converter. The valve receives 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.

Bore wear around the TCC regulator valve can negatively affect torque converter lockup. Bore wear around the valve can reduce converter apply flow, converter release flow and cooler flow. Boost sleeve wear can result in signal fluid loss and prevent the torque converter lockup. Correcting these concerns would normally require replacing the valve body.

Reconditioning the bore and installing the Sonnax oversized TCC regulator valve kit 105740-16K corrects the lockup issues along with restoring the proper hydraulic integrity of the circuit.

• Hardcoat anodized aluminum valve combats premature wear
• Highly wear-resistant boost valve sleeve increases life of part
• Oversized valve maintains OE functions and pressures