Vehicles with listed GM transmissions may have a number of TCC apply problems. Bore wear at the TCC regulator valve can cause no TCC apply or slipping on engagement, harsh shifts, loss of performance and fuel economy, and fluid overheat. If the valve is stuck in the apply position, the result is harsh TCC apply. If the valve is stuck in the release position, no TCC apply or TCC slip will result. Reconditioning the bore and installing Sonnax oversized TCC regulator valve kit 104740-07K will restore proper valve function, resulting in proper TCC apply.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.