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-14K is a standard 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 for usage details and other boost valve options.
Learn More About Zip Valve™ Drop-In Repairs

More From This Category

MANLEY Valve, Race Master, Intake, 37.5mm Head Dia, 0.2355 in. Stem Dia, 4.722 Length, For Ford 5.0L, Each

MANLEY Valve, Race Master, Intake, 37.5mm Head Dia, 0.2355 in. Stem Dia, 4.722 Length, For Ford 5.0L, Each

$51.07

Sonnax Oversized Solenoid Switch Valve & Plug Kit, 40Tes/41Tes/42Le/42Rle/RFE, Each

Sonnax Oversized Solenoid Switch Valve & Plug Kit, 40Tes/41Tes/42Le/42Rle/RFE, Each

$103.01

MANLEY Valve, Severe Duty, Exhaust, 1.625 in. Head Dia, 0.3415 in. Stem Dia, 4.911 in. Length, SBC, Set of 8

MANLEY Valve, Severe Duty, Exhaust, 1.625 in. Head Dia, 0.3415 in. Stem Dia, 4.911 in. Length, SBC, Set of 8

$607.34

MANLEY Valve, Race Flo, Intake, 2.1 in. Head Dia, 0.3125 in. Stem Dia, 4.99 in. Length, For Chrysler HEMI, Set of 8

MANLEY Valve, Race Flo, Intake, 2.1 in. Head Dia, 0.3125 in. Stem Dia, 4.99 in. Length, For Chrysler HEMI, Set of 8

$400.37

MANLEY Valve, Severe Duty, Intake, 1.72 in. Head Dia, 0.3415 in. Stem Dia, 5.14 in. Length, SBC, Set of 8

MANLEY Valve, Severe Duty, Intake, 1.72 in. Head Dia, 0.3415 in. Stem Dia, 5.14 in. Length, SBC, Set of 8

$628.35

MANLEY Valve, Race Master, Exhaust, 1.615 in. Head Dia, 0.3136 in. Stem Dia, 5.23 in. Length, For Chevrolet LS7, Each

MANLEY Valve, Race Master, Exhaust, 1.615 in. Head Dia, 0.3136 in. Stem Dia, 5.23 in. Length, For Chevrolet LS7, Each

$51.07