Boost Valve Kit With O-Rings Sonnax 4L80E 4L85E

Sonnax Boost Valve Kit for 4L80-E, 4L85-E GM 4L80-E and 4L85-E transmissions often encounter issues like uncontrollable line rise (up to 500-600 psi), high line pressure in Reverse, buzzing noises, and broken direct clutch drums or cases. These problems are typically caused by reverse boost oil entering the torque signal circuit due to wear-induced leaks at the sleeve and oil leakage past the aluminum balance plug. The Sonnax boost valve kit 34200-01K effectively addresses these issues. Key Features: Hardened steel boost valve with over 20% wider spools for enhanced durability and increased sealing contact area Annular grooves on boost valve spools reduce side loading and prevent wear High-quality steel boost sleeve with external O-rings ensures a positive seal, compensating for pump cover bore wear Includes a replacement aluminum balance oil plug with an O-ring for proper sealing and maintaining back pressure on the pressure regulator valve Drop-in Zip Valve™ parts for quick and easy