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 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 V8 applications and higher line pressure for towing and off-road, use Sonnax TV boost valve kit 77917-03K.

Throttle valve boost valve and sleeve are manufactured from hardened steel for better wear resistance
Kits available in three sizes for .423", .471" and .500" diameters for a variety of applications
Drop-in Zip Valve™ parts install quickly and easily


Sonnax Part No.
Sleeve Dia.
Performance Applications


77917-02K
.423" dia.
Minimum line pressure for V6 applications and smaller vehicles

77917-03K
.471" dia.
Higher line pressure for towing and off-road

77917-04K
.500" dia.
Maximum line pressure and shift feel for high performance applications


Learn More About Zip Valve™ Drop-In Repairs

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