Transmission Parts GM 4L80-E 4L85-E Pump Valve / Sleeve

Symptoms:

Uncontrollable line rise
High line pressure
Broken parts
Broken clutch piston

Cause:

Unregulated EPC pressure forces pressure regulator into high line position.

Correction:

This self-regulating Reverse boost valve regulates EPC pressure to 95–105 psi with the Sonnax drop-in encapsulated relief valve.

4L80-E, 4L85-E

Boost Valve Kit
Part No. 34200-10K

With encapsulated relief valve. O-Ring style

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Common problems in vehicles with GM 4L80-E and 4L85-E transmissions include uncontrollable line rise (upward of 500 psi), high line pressure in Reverse, broken direct clutch drums and/or broken cases. These problems can be caused by excessive EPC torque signal pressure. Sonnax self-regulating boost valve kit 34200-10K eliminates these problems by limiting EPC pressure.

Hardened steel boost valve has an encapsulated relief valve that will allow EPC pressure to exhaust if it exceeds 95-105 psi
Boost valve with 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
Closely toleranced sleeve restores the hydraulic integrity between the valve and sleeve
O-Rings have been added to the sleeve to provide a positive seal that compensates for pump bore wear
Drop-in Zip Valve^™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

Contents

Valve
Sleeve
O-Rings (2)

Valve Body Layout

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.