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. The Sonnax TV boost valve kits [77917-01K] (.423" dia.), 77917-471 (.471" dia.) and 77917-500 (500" dia.) eliminate these problems for a variety of applications. For higher line pressure for towing and off-road, use Sonnax TV boost valve kit 77917-471.

Throttle valve boost valve and sleeve are made from made from hardened steel for better wear resistance
O-Rings on sleeve separate throttle pressure and Reverse boost circuits, providing additional protection against cross-leaks
O-Rings prevent loss of oil between the outside diameter of the throttle valve sleeve and pump body
Drop-in Zip Valve™ parts install quickly and easily


Sonnax Part No.
Sleeve Dia.
Performance Application


[77917-01K]
.423" dia.
Minimum line pressure for V8 applications

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

77917-500
.500" dia
Maximum line pressure & shift feel for high performance applications


Learn More About Zip Valve™ Drop-In Repairs

More From This Category

MANLEY Valve, Severe Duty, Intake, 2.325 in. Head Dia, 0.3415 in. Stem Dia, 6.59 in. Length, BBC, Set of 8

MANLEY Valve, Severe Duty, Intake, 2.325 in. Head Dia, 0.3415 in. Stem Dia, 6.59 in. Length, BBC, Set of 8

$628.35

MANLEY Valve, Street Flo, Exhaust, 1.55 in. Head Dia, 0.3415 in. Stem Dia, 5.08 in. Length, For Ford SB, Set of 8

MANLEY Valve, Street Flo, Exhaust, 1.55 in. Head Dia, 0.3415 in. Stem Dia, 5.08 in. Length, For Ford SB, Set of 8

$280.36

Sonnax Afl/Solenoid Pressure Regulator Valve Kit, Ford, 6F50/55, 6T70/75 Gen I, Each

Sonnax Afl/Solenoid Pressure Regulator Valve Kit, Ford, 6F50/55, 6T70/75 Gen I, Each

$121.22

MANLEY Valve, Severe Duty, Exhaust, 1.9 in. Head Dia, 0.3415 in. Stem Dia, 5.522 in. Length, Set of 8

MANLEY Valve, Severe Duty, Exhaust, 1.9 in. Head Dia, 0.3415 in. Stem Dia, 5.522 in. Length, Set of 8

$607.34

MANLEY Valve, Custom, Titanium, .3415 in. Stem Dia, Each

MANLEY Valve, Custom, Titanium, .3415 in. Stem Dia, Each

$326.62

MANLEY Valve, Race Flo, Intake, 35.5 mm Head Dia, 5.5 mm Stem Dia, 109.22 mm Length, For Honda, Set of 8

MANLEY Valve, Race Flo, Intake, 35.5 mm Head Dia, 5.5 mm Stem Dia, 109.22 mm Length, For Honda, Set of 8

$399.33