Yukon Gear Pinion Install Kit For 2015+ GM 9.5in 12 Bolt Differential

Regearing a 2014-or-newer Silverado, Sierra, Tahoe, Yukon or Suburban that rides on the GM 9.5 in. 12-bolt rear axle means setting a brand-new pinion, and the pinion can only be set correctly on new bearings, a fresh crush sleeve and the right shims. The Yukon Gear & Axle PK GM9.5-12B pinion install kit is the parts set for that job on a truck whose carrier bearings are still healthy. Our listing title says 2015-up; Yukon's own catalog describes it as a kit for 2014-and-up GM 9.5 in. 12-bolt axles.

What a pinion install kit does in the 2014-up GM 9.5 12-bolt

In this axle the pinion gear is carried by two tapered roller bearings: a large head bearing behind the gear teeth and a smaller tail bearing near the yoke. A crush sleeve between them is compressed as the pinion nut is tightened, and that is what sets bearing preload. Shims under the head bearing race set pinion depth, which is how far the pinion teeth reach into the ring gear. New gears almost never share the old pinion's depth, so the shim pack has to be rebuilt from scratch. This kit gives you the Timken head and tail bearings with their races, a pinion shim pack, a new crush sleeve, a pinion seal, and marking compound with a brush for reading the tooth pattern. The listed pinion spline count is 30 and the ring gear uses 12 bolts.

What it does not include matters just as much. Per the parts breakdown we checked, there are no carrier bearings or carrier shims, no pinion nut, no ring gear bolts, no cover gasket and no axle bearings or seals. That is by design: a pinion kit assumes the carrier side bearings are low-mileage and will be reused. If yours are noisy or pitted, step up to the YK GM9.5-12B master overhaul kit instead.

Symptoms that bring these trucks in for gears or a pinion rebuild

• Bigger tires installed and the truck now feels sluggish, shifts late and loses fuel economy, which is the classic reason to regear
• A whine at cruise that changes from drive to coast, often a pinion bearing losing preload
• Fore-and-aft play at the pinion yoke or a clunk when you go from drive to reverse
• Gear oil seeping from the pinion seal and slinging onto the driveshaft
• A G80 locker that has started banging in turns, where the carrier is coming out anyway and the pinion bearings are worth doing at the same time

How to confirm before ordering

Count the cover bolts first: 12 bolts on a 2014-up GM half-ton points to the 9.5 or 9.76, and our GM 9.5 / 9.76 12-bolt problems guide explains how to tell the two apart and how the G80 locker behaves. Then check the RPO sticker in the glovebox or door jamb for the ratio code. To separate a bearing problem from gear wear, drop the driveshaft and spin the pinion by hand; roughness or end play means bearings. Our whine on drive vs coast guide covers what each noise pattern points to.

Fitment

This kit is for the GM 9.5 in. rear axle with the 12-bolt cover on 2014-and-later trucks and SUVs. It is not for the 1979-1997 semi-float 9.5 with a 14-bolt cover, and it is not the right kit for the 1999-2013 AAM 9.5. GM also built a 9.76 in. version of this axle family for 2014-up trucks; the size is cast into the housing, so read it before you order, or send us your year, engine and VIN and we will match it. The kit is designed to go in with a new 2014-up gear set such as the Yukon 3.42 ring and pinion for the 2014-up 9.5 12-bolt. Browse other kits on our rebuild kits page.

Install notes

• Mark and remove the driveshaft, pull the C-clip axles and the carrier, then press off the old pinion bearings and drive out both races.
• Start pinion depth from the old shim and the etchings on the old and new pinion heads, then confirm with a pattern check using the supplied compound. Expect to adjust the shim more than once.
• Use the new crush sleeve every time and tighten the pinion nut in small steps, checking rotating torque as you go. Overshoot means a new sleeve. Our crush sleeve vs solid spacer guide explains why.
• Buy a new pinion nut and new ring gear bolts separately unless the gear set includes them.
• If you are replacing a worn G80 at the same time, the Detroit Truetrac 917A732 and the Dura Grip for 2014-up 9.5/9.76 both suit 3.42-and-up gears.
• Fill with the axle lubricant your owner's manual specifies and take it easy for the first few hundred miles so the new gears can break in. Use a new cover gasket or a clean bead of RTV, since the kit does not include one.

Does PK GM9.5-12B fit my 2014 Silverado 1500?

It is built for the 2014-and-later GM 9.5 in. 12-bolt rear axle. Many 2014-up 1500s have that axle, but some have the 9.76 in. version or the smaller 8.6. Count the cover bolts, read the size casting on the housing, or send us your VIN and we will confirm.

What is the difference between this pinion kit and the master overhaul kit?

The pinion install kit covers only the pinion side: Timken head and tail bearings and races, pinion shims, crush sleeve, pinion seal and marking compound. The YK GM9.5-12B master kit adds carrier bearings and races, carrier shims and more small parts. Use the pinion kit only when the carrier bearings are low-mileage and quiet.

Does the kit come with a pinion nut and ring gear bolts?

No. The parts breakdown we checked lists no pinion nut, no ring gear bolts, no cover gasket and no axle seals. Plan to buy a new pinion nut and ring gear bolts, or confirm your gear set includes them.

Can I reuse the crush sleeve or the old pinion shims?

Do not reuse the crush sleeve; a new one is in the kit. The old shim is only a starting point, because a new pinion usually needs a different depth. Set it with the supplied shims and confirm with a tooth contact pattern.

What gear oil goes in after the install?

Use the axle lubricant and capacity listed in your owner's manual for your truck and axle. Change it after the break-in miles, since new gears shed fine metal while the teeth lap in.