77898E-14K - Sonnax 4L60E 4L65E Transmission Boost Valve Kit

4L60E 4L65E Transmission Sonnax Actuator Feed Limit Valve Kit Part No. 77898E-14K Valve 3 Grooves Sleeve O-Rings (3) 1 Extra Replaces late pump design, 1.890” length (short) sleeve, standard OE ratio assemblies. GM 4L60-E, 4L65-E and 4L70-E transmissions 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 boost valve kit 77898E-14K is a standard OE ratio assembly that will restore hydraulic integrity and prevent leakage in units with late-design pumps. See chart below for usage details and other boost valve options.