Boost Valve Kit Sonnax Dia .470in 1.907in Long O-Ring Style 4L60E 4L65E 4L70E

Sonnax Boost Valve Kit for 4L60E, 4L65E Transmissions Early Style, .470" Diameter, OE Ratio, O-ring Style GM 4L60-E and 4L65-E transmissions are often plagued by inadequate line rise, which can lead to the failure of the 3-4 clutch and 2-4 band, or result in poor shift quality. The frequent cycling of the EPC solenoid induces rapid wear on the boost sleeve. This wear allows oil that enters the torque signal orifice to leak past the boost valve and exhaust at the Reverse orifice, compromising line rise. Additionally, Reverse oil can leak both to the sump and back through the torque signal orifice. The external diameter of the boost sleeve is also prone to leakage through the pump body, further reducing pressure rise. The Sonnax boost valve kit, part number 77898E-4K, is designed as a large OE ratio assembly that restores hydraulic integrity and prevents leakage in units with early-style pumps. This kit is part of the Drop-in Zip Valve™ series, designed for