GM 5L40-E, 5L50-E transmissions use a PWM solenoid to route TCC signal oil pressure to operate the TCC control valve, which is biased by spring force. When the computer demands apply, regulated apply pressure is directed to the apply side of the converter clutch. During release, converter feed pressure is fed through the control valve to the release side of the converter clutch. Leakage at the control valve can result in incorrect TCC apply or release and inadequate lubrication of the transmission.

These pumps also have a TCC enable valve, which functions as a safety measure and ensures that the converter will have flow and not overheat if the control valve is stuck on when the converter clutch should be released. If the enable valve bore has excessive wear and leakage, incorrect TCC apply or release can occur.

Reconditioning the bore and installing Sonnax oversized TCC control and enable valve kit 55211-22K restores proper hydraulic sealing clearances to prevent oil leakage that results in converter apply/release complaints. These highly wear-resistant valves allow reuse of the OE springs and salvage dual TCC valve pumps.

• Hardcoat anodized aluminum valves combat premature wear
• Restores proper clearances for hydraulic seal integrity