Yukon Gear Master Overhaul Kit for GM 8.5in Differential with Aftermarket Posi

Yukon Gear YK GM8.5-HD Master Overhaul Kit for GM 8.5in High-Performance Differentials

The YK GM8.5-HD is a complete rebuild kit engineered for General Motors 8.5in differentials equipped with aftermarket positraction or performance limited-slip units. Whether you are restoring a classic muscle car or upgrading a heavy-duty truck differential, the YK GM8.5-HD delivers every component needed for a professional-grade overhaul in one convenient package. Yukon Gear has built this YK GM8.5-HD complete rebuild kit around premium Timken bearings and precision shims so your differential performs reliably from first startup through thousands of miles of hard use.

Features and Benefits

• Premium Timken carrier bearings and pinion bearings rated for high-torque applications
• Precision ground shim sets for accurate pinion depth and carrier preload adjustment
• OEM-quality pinion seal and axle seals to prevent gear oil leaks
• Compatible with aftermarket high-performance positraction and limited-slip units
• Ring gear bolts, pinion nut, and crush sleeve all included so no separate hardware sourcing is needed
• Gear marking compound and brush included to verify contact pattern during setup
• Thread-locking compound included for ring gear bolt installation
• Differential cover gasket included for a clean, leak-free reinstall
• All components sourced and packaged by Yukon Gear for guaranteed fitment and quality consistency

Fitment

Specifications

What's Included

• Timken carrier bearings with races (2 sets)
• Timken pinion bearings with races (front and rear)
• Pinion seal
• Axle seals (pair)
• Complete pinion depth shim set
• Complete carrier shim set
• Ring gear bolts
• Pinion nut
• Crush sleeve
• Thread-locking compound
• Gear marking compound with brush
• Differential cover gasket

Frequently Asked Questions

Q: What differential does the YK GM8.5-HD fit?
A: The YK GM8.5-HD is designed for the General Motors 8.5in differential when equipped with an aftermarket positraction or performance limited-slip carrier.

Q: Does this kit work with a factory GM open carrier?
A: No. The YK GM8.5-HD is specifically designed for use with aftermarket positraction units. If your differential has the original open carrier, see the standard YK GM8.5 kit instead.

Q: Are the bearings in this kit genuine Timken?
A: Yes. The YK GM8.5-HD complete rebuild kit includes genuine Timken bearings, which are the industry standard for differential rebuilds.

Q: Will installing this kit void my vehicle warranty?
A: Under the Magnuson-Moss Warranty Act, a vehicle manufacturer cannot void your powertrain warranty solely because you installed an aftermarket part. Warranty coverage may only be denied if the aftermarket part is proven to have caused the failure.

Q: Do I need any additional parts to complete my rebuild?
A: The YK GM8.5-HD includes all critical hardware. You will still need a quality gear oil and your choice of ring and pinion gears if you are changing the ratio.

Q: What years does this kit cover?
A: The YK GM8.5-HD covers GM 8.5in differentials from approximately 1970 through 2000 in applicable Chevrolet, Pontiac, and GMC platforms equipped with aftermarket posi. Verify your specific application against the fitment table.

Q: Is professional installation recommended?
A: Differential rebuilds require precise preload and backlash settings. Professional installation or experienced DIY practice with proper tooling is strongly recommended.

Q: Where is the YK GM8.5-HD manufactured?
A: Yukon Gear manufactures and packages the YK GM8.5-HD to strict quality standards, using premium brand-name bearings for reliability.

Installation Instructions

1. Drain differential gear oil and remove axle shafts per your vehicle service manual.
2. Remove the differential cover and clean all mating surfaces thoroughly.
3. Remove the carrier assembly and set aside. Inspect the housing for wear or damage.
4. Remove the pinion and drive flange, noting original shim stack thickness.
5. Press off old pinion bearings and install new Timken pinion bearings from the YK GM8.5-HD kit.
6. Use the included shims to set pinion depth; verify with a dial indicator and marking compound.
7. Press new carrier bearings onto the carrier using the bearing races included in the kit.
8. Install the carrier, set backlash to manufacturer specification, and verify contact pattern.
9. Apply thread-locking compound to ring gear bolts and torque to spec.
10. Install the new pinion seal and torque pinion nut to achieve proper pinion bearing preload.
11. Install the new axle seals, reinstall axle shafts, and torque all fasteners.
12. Install differential cover with new gasket; fill with the specified gear oil grade and quantity.
13. Road test and re-check for leaks after break-in.

California Proposition 65 Warning: This product can expose you to chemicals including lead and lead compounds, which are known to the State of California to cause cancer, birth defects, and other reproductive harm. For more information, visit www.p65warnings.ca.gov.