Common problems in vehicles with GM 4L80-E and 4L85-E transmissions are uncontrollable line rise (upward of 500-600 psi), high line pressure in Reverse, buzzing noise, broken direct clutch drums and/or broken cases. These problems are usually caused by Reverse boost oil that enters the torque signal circuit due to a wear-created cross leak at the sleeve. High line pressure and buzz is created by oil leakage past the aluminum balance plug. Sonnax boost vavle kit 34200-03K eliminates these problems.

Hardened steel boost valve with over 20% wider spools to provide better durability and increased sealing contact area
Boost valve spools have annular grooves to reduce side-loading that causes wear
Valve and sleeve are manufactured to close tolerances to restore proper clearance and hydraulic integrity
Kit includes a replacement aluminum balance oil plug with an O-ring to ensure proper sealing and adequate back pressure on the pressure regulator valve
Drop-in Zip Valve™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

More From This Category

Sonnax Oversized Lockup Relay Valve Kit, Aisin Aw, Aw55-50Sn, Aw55-51Sn, Each

Sonnax Oversized Lockup Relay Valve Kit, Aisin Aw, Aw55-50Sn, Aw55-51Sn, Each

$106.67

MANLEY Valve, Pro Flo, Intake, 2.055 in. Head Dia, 0.3415 in. Stem Dia, 5.111 in. Length, SBC, Set of 8

MANLEY Valve, Pro Flo, Intake, 2.055 in. Head Dia, 0.3415 in. Stem Dia, 5.111 in. Length, SBC, Set of 8

$607.34

MANLEY Valve, Titanium, Intake, Bead Loc, 2.15 in. Head Dia, 0.3415 in. Stem Dia, 5.34 in. Length, Each

MANLEY Valve, Titanium, Intake, Bead Loc, 2.15 in. Head Dia, 0.3415 in. Stem Dia, 5.34 in. Length, Each

$302.72

MANLEY Valve, Race Master, Exhaust, 1.94 in. Head Dia, 0.3415 in. Stem Dia, 5.522 in. Length, BBC, Set of 8

MANLEY Valve, Race Master, Exhaust, 1.94 in. Head Dia, 0.3415 in. Stem Dia, 5.522 in. Length, BBC, Set of 8

$380.66

MANLEY Valve, Race Master, Intake, 37mm Head Dia, 0.2355 in. Stem Dia, 4.722 Length, For Ford 5.0L, Set of 8

MANLEY Valve, Race Master, Intake, 37mm Head Dia, 0.2355 in. Stem Dia, 4.722 Length, For Ford 5.0L, Set of 8

$408.60

MANLEY Valve, Budget Replacement, Intake, 2.02 in. Head Dia, 0.3415 in. Stem Dia, 4.88 in. Length, SBC, Each

MANLEY Valve, Budget Replacement, Intake, 2.02 in. Head Dia, 0.3415 in. Stem Dia, 4.88 in. Length, SBC, Each

$18.76