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Drivetrain› Differentials and Rear-End Components

Eaton

Differential Builder Kit

$711.84 $648.00 Save $63.84

SKU: POSI-GM8.6-RA

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

It operates by smoothly transferring power to the wheel with better grip, preventing wheel slip. This unit features race-bred carbon friction discs and a rebuildable design that can be custom-tuned for specific performance needs.
Show original supplier description
The Eaton Posi Limited Slip Differential provides enhanced traction control for muscle cars, street rods, light duty pickups, and race cars. Its operation is automatic, requiring no driver input, as preloaded carbon disc clutch packs, located behind each differential side gear, smoothly transfer power to the wheel with more grip when torque input changes. This prevents wheel slip before it can start. Featuring a superior, rebuildable design with race-bred carbon friction discs, the Eaton Posi offers limited-slip operation and smooth, automatic engagement. It is tunable via various spring packs for customized performance. For proper function, a quality GL5 petroleum-based or synthetic oil with sufficient friction modifier must be used. This Posi unit is designed for GM 8.5-inch and 8.6-inch rear differentials with 30 spline axles and a carrier break of 2.73 and up. It is compatible with Chevy vehicles from 1989-2018. However, it specifically "does not fit 1999+ with drum brakes." Additionally, while 8.6 carriers may fit 8.5 axles, 8.5 carriers may not fit 8.6 axles without a special bearing race.

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

BrandEaton
Part NumberPOSI-GM8.6-RA
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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