Kit, Sleeve, Boost, Valve, .490" Diameter, Early Pump, 4L60E, 4L65E, 4L70E, GM (93-05)

Boost Valve Kit, 4L60E,4L65E, 4L70E, GM, "Factory" Style,.490" diameter  

Vehicles with a 4L60-E, 4L65-E or 4L70-E transmission 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 offers four versions of reverse boost valve and sleeve kits for early pumps. There are two O-ringed versions, 77898E-K for oversized ratio and 77898E-4K for OE ratio, and two factorystyle versions, 77898E-3K for oversized ratio early pumps and 77898E-6K for OE ratio.

*NOTE: The 4L60-E, 4L65-E and 4L70-E transmissions will not function properly if the wrong early vs. late design assembly is installed.

Sonnax boost valve kit 77898E-3K is an increased ratio assembly that will restore hydraulic integrity and prevent leakage in units with early-design pumps. See chart for usage details and other boost valve options.

Contents

Sleeve

Valve .490", No Groove

Warning:

OE has made multiple pump design changes. Transmission will not function properly if the wrong length sleeve is installed. Verify length of OE sleeve and select Sonnax kit with equivalent sleeve length.