A common problem in GM 200-4R and 4L60 transmissions is burned bands and/or 3-4 clutches. This failure can be reduced by eliminating throttle boost oil leakage. Sonnax drop-in TV boost valve kits 77917-02K (.423" dia.), 77917-03K (.471" dia.) and 77917-04K (.500" dia.) eliminate these problems in a variety of applications. For maximum pressure and shift feel for high performance applications, use Sonnax TV boost valve kit 77917-04K.
Throttle valve boost valve and sleeve are manufactured from hardened steel for better wear resistance