Yukon Gear High Performance Gear Set For GM 8.5in & 8.6in in a 4.11 Ratio
Put 33 or 35 inch tires on a Silverado, Sierra, Tahoe or Yukon half-ton and the factory 3.42 or 3.73 gears suddenly feel like you are towing with the parking brake on: the transmission hunts between gears, it will not hold overdrive on a grade, and the speedometer reads low. The Yukon YG GM8.5-411 is a 4.11 ratio ring and pinion that brings that lost leverage back for the GM 8.5 and 8.6 inch 10-bolt. It uses an 8.50 inch ring gear, 10 ring gear bolts and a 30-spline pinion, and it is also the set people use to replace a worn or chipped factory 4.10.
The pinion turns 4.11 times for every turn of the ring gear and the axle shafts. Compared with a 3.42 that is about 20 percent more multiplication at the tires, which is roughly what a jump from a 31 to a 35 inch tire takes away. A quick way to check it: engine RPM equals MPH times ratio times 336, divided by tire diameter. At 65 mph on a 33 inch tire a 4.11 turns about 2,720 RPM in a 1:1 gear, and about 1,900 RPM with a 0.70 overdrive. That keeps the converter locked and the engine in its torque band instead of downshifting every hill. On a stock-tire truck the same 4.11 is a towing or acceleration gear, at the cost of higher cruise RPM.
Read the ratio off the axle code tag or the build sheet, or count driveshaft turns against one full tire turn with the other tire on the ground. Then look at what is really wrong. A howl at one road speed is gear wear or a bad pattern; a growl that changes when you swerve is usually a wheel bearing. If the gears are fine and you are only fighting a tire change, this set is a bolt-in ratio swap. If you are staying on stock-size tires, a 3.73 Yukon set keeps cruise RPM lower, and for 37s and up the 4.56 set is the better match.
Yukon's application chart for YG GM8.5-411 is long. It covers the 1970s and 1980s GM car 8.5 rear (Camaro, Firebird, Nova, Cutlass, Monte Carlo, Grand Prix, Impala and Caprice among them), 1979-1986 C10 and K10 pickups and K5 Blazers, the 8.6 rear in 1999-2017 Silverado and Sierra 1500 and 1999-2013 Tahoe, Yukon and Escalade, 2004-2012 Colorado and Canyon, 2002-2009 Trailblazer and Envoy, 2006-2010 H3, and Express and Savana 1500 vans. It also lists the 8.5 front axle used under 1977-1991 K-series trucks, Blazers and Suburbans. Many of those rows note a factory 4.10, which this 4.11 replaces. Not every listed vehicle has the 10-bolt in every trim, so confirm the ring gear size and 10-bolt cover on your axle, or send us the year and VIN and we will check it. The 8.6 IRS rear in the Camaro and the 8.25 IFS front are different axles and do not take this set.
A ratio change in a 10-bolt is a full setup job, not a swap. Expect to set pinion depth with shims (Yukon's chart starts from 0.037 in. for the GM 8.5 and 8.6), set new-bearing pinion preload at 14-19 in-lb, then set backlash at 0.006-0.011 in. and read the contact pattern with marking compound. Ring gear bolts go to 65 ft-lb and bearing caps to 60 ft-lb. New bearings, races, crush sleeve and pinion seal are cheap insurance, so pair the gears with a GM 8.5 master overhaul kit on older axles or a 1999-2008 8.6 overhaul kit on the trucks. A 4.11 fits carriers made for 2.73 and numerically higher ratios, so if the carrier is coming out anyway, this is the time to add an Eaton Truetrac. Fill with 75W-90 gear oil (add friction modifier only if a clutch-type posi is installed), drive easy for the first 15-20 miles, let it cool, and change the oil after the first 500 miles. Recalibrate the speedometer and shift tables for the new ratio and tire size.
| Brand | Yukon Gear & Axle |
| Part number | YG GM8.5-411 |
| Fits | Yukon Gear High Performance Gear Set For GM 8.5in & 8.6in in a 4.11 Ratio |
| Type | Final Drive Gears |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is a common pick for 33 to 35 inch tires on 1999-2017 Silverado, Sierra and Tahoe trucks with a four-speed or six-speed automatic. Run the RPM math at your usual highway speed and tire size before ordering: about 1,800-2,200 RPM in overdrive is a comfortable target for most V8s.
Yes. Yukon lists this 4.11 set against GM applications that came with a 4.10 option. The speedometer change between 4.10 and 4.11 is too small to notice.
Not on a GM 8.5 or 8.6 with an original 2.73-or-higher carrier. If your axle came with a very tall 2.56 or lower ratio, check the carrier before ordering, because it may sit on a different carrier break.
Yukon includes the 8.5 front axle under 1977-1991 K-series trucks, Blazers and Suburbans in its chart for this set. The front and rear ratios must match, so order a rear set at the same time if the rear is changing too.
A master install or overhaul kit with pinion and carrier bearings, races, shims, crush sleeve, pinion seal and ring gear bolts, plus 75W-90 gear oil. Plan on gear marking compound, a dial indicator and an inch-pound torque wrench, or have a gear shop do the setup.
