GM 4L60-E, 4L65-E and 4L70-E transmissions frequently have poor line rise, which can result in 3-4 clutch, 2-4 band failure or poor shift quality. The duty cycle of the EPC solenoid causes the boost sleeve to wear quickly. Oil entering the torque signal orifice leaks past the boost valve and exhausts at the Reverse orifice, resulting in poor line rise. Reverse oil can exhaust both to the sump and back through the torque signal orifice. The outside diameter of the boost sleeve also allows some leakage through the pump body, which decreases pressure rise.
Sonnax boost valve kit 77898E-16K is a large OE ratio assembly that will restore hydraulic integrity and prevent leakage in units with late-style pumps. Drop-in Zip Valve™ parts install quickly and easily. See chart below for usage details and other boost valve options.
Learn More About Zip Valve™ Drop-In Repairs

More From This Category

MANLEY Valve, Race Master, Exhaust, Bead Loc, 1.575 in. Head Dia, 0.3125 in. Stem Dia, 4.845 in. Length, For Chrysler HEMI, Set of 8

MANLEY Valve, Race Master, Exhaust, Bead Loc, 1.575 in. Head Dia, 0.3125 in. Stem Dia, 4.845 in. Length, For Chrysler HEMI, Set of 8

$400.37

MANLEY Valve, Race Flo, Intake, 33.0 mm Head Dia, 6 mm Stem Dia, 98.05 mm Length, For Toyota Supra, Each

MANLEY Valve, Race Flo, Intake, 33.0 mm Head Dia, 6 mm Stem Dia, 98.05 mm Length, For Toyota Supra, Each

$49.91

MANLEY Valve, Custom, Titanium, .3415 in. Stem Dia, Set of 8

MANLEY Valve, Custom, Titanium, .3415 in. Stem Dia, Set of 8

$2,293.03

MANLEY Valve, Race Master, Exhaust, Bead Loc, 38mm in. Head Dia, 0.313 in. Stem Dia, 4.606 in. Length, Volkswagen, Each

MANLEY Valve, Race Master, Exhaust, Bead Loc, 38mm in. Head Dia, 0.313 in. Stem Dia, 4.606 in. Length, Volkswagen, Each

$47.58

MANLEY Valve, Race Master, For Toyota 3UR-FE, 38.5mm Head Dia, Set of 8

MANLEY Valve, Race Master, For Toyota 3UR-FE, 38.5mm Head Dia, Set of 8

$391.24

MANLEY Valve, Severe Duty, Intake, 2.08 in. Head Dia, 0.3415 in. Stem Dia, 5.44 in. Length, SBC, Each

MANLEY Valve, Severe Duty, Intake, 2.08 in. Head Dia, 0.3415 in. Stem Dia, 5.44 in. Length, SBC, Each

$78.54