4L80E 4L85E Reverse Servo Piston with Hump Billet Aluminum HD 1997-up 34912AC

Modified Item: No

Country/Region of Manufacture: United States

Custom Bundle: No

Surface Finish: New

Manufacturer Part Number: 34912AC

Brand: Adapt-A-Case

Fitment Type: Direct Replacement

Non-Domestic Product: No

Transmission Type: Automatic

Manufacturer Warranty: Unspecified Length

Overall, the 4L80E is a fairly heavy-duty transmission.

One of its lesser points is the cast aluminum reverse servo piston. This weak link is prone to breakage while enduring the repetitive cycling that occurs in plow truck applications, when the boost valve has worn or when the pressure spikes.

Our solution is this burly billet aluminum version. A direct replacement, it’s much stronger than the OEM casting by nature. Our engineers have made an effective leap forward in design to ensure your customers’ demanded durability.

The factory unit is weak where it needs to be strong: the area around the apply pin. We’ve engineered ours far thicker than the original to combat the stresses of any side loading. Another touch is the additional thickness above the sealing ring groove that helps to stabilize the piston in the bore.

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