Drivetrain› Automatic Transmissions and Components

Sonnax

Heavy Duty Low/Reverse Servo Piston

$67.00

SKU: 34914-02

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Sonnax 34914-02 is a heavy duty low/reverse servo piston designed for GM 4L80-E and 4L85-E transmissions. It is a direct replacement upgrade for OE cast aluminum servo pistons, which are known to be brittle and prone to breaking. This upgrade is made from high-strength, billet aluminum to prevent failure.
Show original supplier description
The Sonnax Heavy Duty Low/Reverse Servo Piston (Part No. 34914-02) offers a robust upgrade for 1996 and later GM 4L80-E and 4L85-E automatic transmissions. It directly replaces the OE cast aluminum servo pistons, which are susceptible to brittleness and breakage, leading to transmission failure. This Sonnax piston is engineered from high-strength, billet aluminum, providing a durable solution to prevent common failures. It is a direct fit upgrade, ensuring seamless integration into the existing transmission components. The part number 34914-02 is specifically designed to address the known weaknesses of the original equipment pistons, offering enhanced durability and peace of mind for transmission rebuilds and performance applications.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandSonnax
Part Number34914-02
CategoryDrivetrain
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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