Transmission Parts GM 200-4R 4L60 Pump Valve / Sleeve

Symptoms:

Low Reverse boost
Delayed Reverse
Low line pressure
Poor upshift in manual low

Cause:

Worn reverse boost valve sleeve or wear at pump body.

Correction:

Sonnax large ratio, drop-in Reverse boost valve kit, made from hardened steel, restores reverse boost pressure control and prevents premature wear related failures.

200-4R, 4L60

Reverse Boost Valve Kit
Part No. K77898A

Large Ratio, Factory Style, No O-Rings

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Vehicles with GM 200-4R and 4L60 transmissions often have complaints of poor Reverse boost or upshifts in manual low. This complaint is generally caused by a worn Reverse boost valve sleeve or wear at the pump body. To resolve these problems, Sonnax offers larger ratio (.283"), factory-style Reverse boost valve kit K77898A.

Due to the differences in the thermal expansion rate of steel and aluminum when the transmission approaches operating temperature, the sleeve has been allowed excessive clearance and scrubs the bore.

Sleeve and valve are made from hardened steel for increased wear resistance
Sleeve lands have been lengthened to add better sealing and stabilizing capabilities to prevent bore wear
The reverse boost valve spool lands have been lengthened to aid in maintaining hydraulic integrity
Drop-in Zip Valve™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

Contents

Valve
Sleeve

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.