Yukon Gear High Performance Gear Set For GM 8.5in & 8.6in in a 4.56 Ratio

Yukon Gear Ring and Pinion Set for GM 8.5 and 8.6-Inch 10-Bolt Differential in 4.56 Ratio

The YG GM8.5-456 from Yukon Gear and Axle is a high-performance 4.56 ratio ring and pinion gear set for the GM 8.5-inch and 8.6-inch 10-bolt rear differential. The GM 8.5 and 8.6 are the standard rear axles in a vast range of Chevrolet and GMC trucks, SUVs, and vans from 1980 through 2017, and the YG GM8.5-456 is the go-to regear choice for builds running 33-to-35-inch tires seeking a strong towing and off-road improvement without committing to the most extreme ratios. Yukon machines the YG GM8.5-456 from premium alloy steel using advanced tooth geometry validated in two dedicated in-house quality labs. The result is a gear set that delivers reliable, smooth operation under daily driving and sustained off-road loads alike. For Silverado, Tahoe, Suburban, Sierra, Yukon, and Escalade owners looking to recapture performance lost to a lift and oversized tires, the YG GM8.5-456 is a proven direct-fit upgrade backed by Yukon's Y.E.S. lifetime warranty plan.

Key Features and Benefits

• 4.56 Gear Ratio: Ideal for builds running 33-to-35-inch tires needing improved low-end torque for towing and off-road use
• GM 8.5 and 8.6 Fitment: Compatible with both 8.5-inch and 8.6-inch 10-bolt rear axles across 1980 to 2017 applications
• 30-Spline Pinion: Matches the GM 10-bolt carrier standard for a direct-fit installation
• Premium Alloy Steel: High-strength material precision machined and heat-treated for long service life
• Advanced Tooth Geometry: Optimized profile minimizes heat and friction under continuous load
• Dual Lab Verification: Every gear set tested in Yukon's in-house quality labs before shipment
• Y.E.S. Plan Eligible: Optional lifetime no-questions-asked warranty upgrade available

Fitment

Specs

What Is Included

• Ring gear
• Pinion gear
• Pinion nut

Frequently Asked Questions

• Q: What vehicles does the YG GM8.5-456 fit?
  A: The YG GM8.5-456 fits GM 8.5-inch and 8.6-inch 10-bolt rear differentials in Chevrolet Silverado 1500, Tahoe, Suburban, Avalanche, GMC Sierra 1500, Yukon, and Cadillac Escalade from 1980 through 2017.
• Q: What tire size works best with the 4.56 ratio?
  A: The YG GM8.5-456 is well-matched for lifted trucks running 33-to-35-inch tires, restoring low-end torque and towing performance lost due to the increase in tire circumference.
• Q: Does the 4.56 ratio require a carrier change?
  A: It depends on your existing carrier. The GM 8.5 uses separate carriers for numerically lower and higher ratios. Verify whether your current carrier accepts the 4.56 before ordering.
• Q: What install kit should I use with the YG GM8.5-456?
  A: Yukon recommends a GM 8.5 master install kit that includes new pinion and carrier bearings, shims, seals, and a pinion nut for proper preload and long service life.
• Q: Does installing the YG GM8.5-456 affect my factory warranty?
  A: Under the Magnuson-Moss Warranty Act, a dealer must prove the YG GM8.5-456 caused the failure before denying a warranty claim. Installing an aftermarket gear set alone is not sufficient grounds for denial.
• Q: Does this set fit both the 8.5 and 8.6-inch axles?
  A: Yes. The YG GM8.5-456 is engineered to fit both the 8.5-inch and 8.6-inch GM 10-bolt axles, which use the same ring and pinion dimensions.
• Q: What warranty is included with the YG GM8.5-456?
  A: Yukon covers the YG GM8.5-456 for one year against manufacturing defects. The Y.E.S. plan extends coverage to lifetime no-questions-asked protection.
• Q: Is professional installation required?
  A: Yes. Installing the YG GM8.5-456 requires precise pinion depth, ring gear backlash, and bearing preload setup that demands specialized tools and experience. Professional installation is strongly recommended.

Installation Instructions

1. Safely lift and support the vehicle. Drain the rear differential gear oil.
2. Mark and remove the driveshaft and rear axle shafts.
3. Pull the differential cover and clean the housing completely.
4. Record existing ring gear backlash and pinion preload for reference.
5. Remove bearing caps and pull the carrier and pinion assemblies.
6. Install new pinion bearings from the GM 8.5 master install kit onto the YG GM8.5-456 pinion.
7. Shim pinion depth using a dial indicator until correct tooth contact geometry is achieved.
8. Press the new ring gear onto the correct carrier and torque ring gear bolts in a cross pattern to specification.
9. Install the carrier, set bearing preload, and adjust backlash to 0.006 to 0.010 inch.
10. Check contact pattern with gear marking compound; adjust pinion depth or backlash if needed.
11. Reinstall cover with RTV or gasket. Fill with GM 8.5 specified gear oil.
12. Reinstall axle shafts, driveshaft, and wheels, torquing all fasteners to specification.
13. Follow Yukon break-in procedure before sustained towing or off-road use.

Proposition 65 Warning: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.