GM 4L60E / 4L65E Boost Valve & Sleeve Kit

Sonnax boost valve kit 77898E-K is a increased ratio assembly that will restore hydraulic integrity and prevent leakage in units with early-design pumps. OEM RATIO .490' (O-RING STYLE) 1 ID GROOVE ON END (LATE 4L60E,4L65E & 4L70E WILL NOT FUNCTION PROPERLY IF WRONG VALVE IS INSTALLED)