USA Standard Gear

GM 8.5-inch Differential Master Overhaul Kit

$190.00

SKU: ZK GM8.5-HD

In Stock
In Stock
Ships by Aug 31
Free Shipping over $200
$100 Minimum Order
30 Days Return

Description

The USA Standard Gear Master Overhaul Kit (ZK GM8.5-HD) is engineered to provide a complete solution for rebuilding GM 8.5-inch differentials, specifically those equipped with aftermarket Positraction units. This comprehensive kit streamlines the rebuilding process by consolidating all essential components under a single part number. The kit includes carrier bearings and races, pinion bearings and races, a pinion seal, a complete shim kit, ring gear bolts, a pinion nut, and a crush sleeve where applicable. Further enhancing its utility, the ZK GM8.5-HD kit also contains thread locker, marking compound with brush, and a gasket. This ensures that all necessary consumables and specialized tools for a professional differential overhaul are readily available, minimizing the need for separate purchases and simplifying the installation. The primary application for this kit is GM 8.5-inch rear differentials that feature aftermarket Positraction.

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

Fitment Guaranteed

Don’t gamble
on fit.

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

Available on iOS & Android

Specifications

BrandUSA Standard Gear
Part NumberZK GM8.5-HD
CategoryDrivetrain

We’re here — turning wrenches, just like you.

Call us, follow along, or come say hi.

(760) 282-4645 Instagram Google

Buy with Confidence

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.

View Full Return Policy

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.

View Full Shipping Policy