Zumbrota Drivetrain

GM 8.5" Re-Gear Kit 3.90 Ratio

$708.89

SKU: YGK2332

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

Description

The Zumbrota Drivetrain Yukon Muscle Car Re-Gear Kit provides an aggressive gear ratio upgrade to enhance a vehicle's launching capability and acceleration. This kit is specifically designed for GM 8.5-inch differentials and includes the ring and pinion gear set, along with all required bearings and installation hardware. Key specifications for this re-gear kit include a 30-spline pinion gear, a 3.90 gear ratio, and a 10-bolt ring gear. The kit also comes with 2.25-inch OD bearings, ensuring comprehensive coverage for the differential upgrade. This product is intended for muscle car applications and hot-rodded vehicles utilizing the GM 8.5” differential. Fitment details provided indicate compatibility with specific models such as the 1970-1981 Firebird Trans Am and 1970-1977 GTO, as well as approximately 25 other models that use the GM 8.5” differential. It is suitable for any vehicle hot-rodded with this specific differential configuration.

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

BrandZumbrota Drivetrain
Part NumberYGK2332
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