In GM 4T40-E and 4T45-E units, the boost valve assembly is activated by torque signal pressure from the pressure control solenoid and reverse pressure to aid in adjusting line pressure at the pressure regulator valve. This boost valve is continuously oscillating in the sleeve, which leads to wear and hydraulic leakage. When wear occurs, critical oil pressure is allowed to cross leak between the circuits or leak to exhaust. These leaks can result in either no line rise or an unwanted increase in line pressure. Sonnax boost valve kit 33886-03K that the hydraulic integrity and controls line rise.

Replacement boost sleeve delivers oil 360° around the valve, reducing side load
Sleeve is manufactured from highly wear-resistant aluminum
Hardcoat anodized aluminum valve combats premature wear
Tight tolerances on the sleeve and valve maintain an ideal fit that prevents leakage
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