Vehicles with a GM TH400 and TH425 transmissions frequently have poor line rise, soft 1-2 and/or 2-3 shifts and/or Reverse engagement difficulties. These problems can be caused by the reciprocating boost valve wearing the I.D. of the boost sleeve. When this occurs, oil that enters the modulated throttle valve orifice leaks past the boost valve and exhausts through the Reverse orifice or to the sump, resulting in poor line rise. Reverse oil also can exhaust both to the sump and back through the modulated TV orifice. The O.D. of the boost sleeve also allows some leakage through the pump body, which can increase boost oil loss. Sonnax boost valve kit 34910-01K eliminates the above problems by restoring hydraulic integrity and providing a positive seal with the pump bore.

Valve and sleeve manufactured from high-quality steel
O-Rings provide additional protection against leakage through the pump body to assist in maintaining pressure in the circuits which supply the boost valve
Uses the same valve spool diameters as the OE version to retain factory shifts
Drop-in Zip Valve™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

More From This Category

MANLEY Valve Spring and Retainer Kit, .430 in. Max Lift, For Toyota Supra, 2JZGT/2JZGTE 6 cyl, w/ Valve Locks, Kit

MANLEY Valve Spring and Retainer Kit, .430 in. Max Lift, For Toyota Supra, 2JZGT/2JZGTE 6 cyl, w/ Valve Locks, Kit

$1,242.07

Trick Flow Valve Spring, PAC Racing, Beehive, .959 in./1.061 in. O.D, 191 lbs./in. Rate, 1.020 in. Coil Bind, Each

Trick Flow Valve Spring, PAC Racing, Beehive, .959 in./1.061 in. O.D, 191 lbs./in. Rate, 1.020 in. Coil Bind, Each

$46.98

AFR Valve Seat, SBF NHRA Exhaust 1.650 OD X 1.250 ID x .375

AFR Valve Seat, SBF NHRA Exhaust 1.650 OD X 1.250 ID x .375

$25.04

MANLEY Valve Spring Locator, Inside, Heat-Treated, Fits 1.16 in. OD. Spring, .5 in. ID, 1.1 in. OD, .095 in. Thick, Black, Each

MANLEY Valve Spring Locator, Inside, Heat-Treated, Fits 1.16 in. OD. Spring, .5 in. ID, 1.1 in. OD, .095 in. Thick, Black, Each

$11.77

COMP Cams Steel Retainer, Tool, 7 Degree, 8mm Valve w/ 26925 Springs, Set of 16

COMP Cams Steel Retainer, Tool, 7 Degree, 8mm Valve w/ 26925 Springs, Set of 16

$469.13

MANLEY Valve Spring Locator, Inside, Heat-Treated, Fits 1.311 in. OD. Spring, .52 in. ID, 1.29 in. OD, .19 in. Thick, Black, Each

MANLEY Valve Spring Locator, Inside, Heat-Treated, Fits 1.311 in. OD. Spring, .52 in. ID, 1.29 in. OD, .19 in. Thick, Black, Each

$11.77