Drivetrain› Automatic Transmissions and Components

Sonnax

Heavy-Duty Reaction Shell Kit

$179.00

SKU: 77749-02K

In Stock
In Stock
Ships by Aug 5
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30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Description

The Sonnax SmartShell Heavy Duty Reaction Shell Kit (77749-02K) addresses common failures in GM 4L60, 4L60-E, 4L65-E, and 4L70-E transmissions. It features a heavy-duty reaction shell constructed from thicker steel, a custom roller clutch race, and an enclosed thrust bearing.

MIA's Description

The Sonnax 77749-02K is a heavy-duty reaction shell kit designed to prevent damage to the rear planetary assembly in GM 4L60, 4L60-E, 4L65-E, and 4L70-E transmissions. This kit includes a reinforced, heavier-duty reaction shell and replaces the OE plastic washer with a large thrust bearing and roller clutch race.

Fitment

Fitment Guaranteed

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Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

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Specifications

BrandSonnax
Part Number77749-02K
CategoryDrivetrain

Buy with Confidence

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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