Boost Valve Kit Sonnax 4L80E 4L85E MT1 MN8

Boost Valve Kit 4L80-E, 4L85-E From Sonnax Compatible with '91-later units featuring a factory-style sleeve (no O-rings). Can also be retrofitted to '89-91 units. GM 4L80-E and 4L85-E transmissions in various vehicles are often plagued by issues such as uncontrollable line rise (surpassing 500-600 psi), excessive line pressure in Reverse, buzzing noises, fractured direct clutch drums, and/or damaged cases. A common root cause of these issues is the infiltration of Reverse boost oil into the torque signal circuit, a result of a wear-induced cross leak at the sleeve. Additionally, high line pressure and buzzing noises may arise from oil leakage past the aluminum balance plug. The Sonnax boost valve kit 34200-03K is designed to effectively address and eliminate these problems, restoring optimal transmission performance. Key Features: Features a hardened steel boost valve, designed with spools that are over 20% wider, ensuring enhanced durability and a larger sealing contact area Boost va