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

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Symptoms:

Burnt Reverse band
Delayed Reverse
No Reverse
No engine braking in manual low

Cause:

Wear at the #7 Low/Reverse checkball seat can result in loss of rear band apply (RBA) pressure due to exhaust of low or RBA pressure in manual 1st or Reverse.

Correction:

Restore hydraulic control and prevent premature wear by installing drop-in Sonnax #7 low/reverse checkball seat.

4L80-E, 4L85-E

#7 Low/Reverse Checkball Seat
Part No. 34200-52

Fits '95-later units.

Package Quantity: 5

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Vehicles with GM 4L80-E and 4L85-E transmissions commonly exhibit wear in the #7 Low/Reverse checkball seat location. This issue is caused by normal movement of the checkball and slight movement of the seat within the bore over time. As wear progresses, sealing function of the checkball seat becomes compromised and results in loss of rear band apply (RBA) pressure. This can result in a burnt rear band, delayed or no Reverse and loss of engine braking in manual low.

Installing Sonnax #7 Low/Reverse checkball seat 34200-52 restores the hydraulic integrity of this circuit to re-establish normal pressure and performance.

Replaces worn checkball seat to correct loss of RBA apply pressure
Checkball seal made from high-strength, wear-resistant aluminum for added durability
Drop-in Zip Valve^™ parts install quickly and easily

Learn More About Zip Valve™ Drop-In Repairs

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.