Product Details

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Common problems in vehicles with a 4L80-E transmission are uncontrollable line rise (upward of 500-600 psi), high line pressure in reverse, buzzing noise, broken direct clutch drums and/or broken cases. These problems are usually caused by reverse boost oil that enters the torque signal circuit due to a wear-created cross leak at the sleeve. High line pressure and buzz is created by oil leakage past the aluminum balance plug. The Sonnax replacement assembly 34200-01K eliminates these problems. Features & Benefits: Hardened steel boost valve has over 20% wider spools to provide better durability and increased sealing contact area. Boost valve spools have annular grooves to reduce side loading that causes wear. Quality steel boost sleeve with external O-rings provides positive seal to compensate for pump cover bore wear. Kit includes a replacement aluminum balance oil plug with an o-ring to ensure proper sealing and adequate back pressure on the pressure regulator valve. Kit includes instructions to retrofit parts dating back to 1989.