GM 8.6 IRS Rear Pinion Bearing Kit, Motive Gear R8.6RPK

Fifth-gen Camaro owners usually come looking for this kit for one of two reasons: they are putting a deeper gear in the 8.6 inch independent rear, or the stock pinion bearings have started to howl on decel and the pinion seal is leaving drips under the car. Motive Gear R8.6RPK is the pinion-side kit for the GM 8.6 IRS used in the 2010-2015 Chevrolet Camaro, with Koyo bearings and the small parts to set pinion depth and preload correctly.

What the pinion bearing kit does in the GM 8.6 IRS

In the Camaro's rear module the pinion is carried by an inner and outer tapered roller bearing. The inner bearing takes most of the thrust from the gear mesh, and the crush sleeve between the two bearings holds preload once the nut is torqued. A shim behind the inner bearing sets pinion depth. A V8 Camaro sends a lot of torque through a relatively compact gear set, so worn or loose pinion bearings show up quickly as noise and a changing contact pattern. Per the listing, the kit includes Koyo inner and outer pinion bearings with races, a pinion seal, a crush sleeve, a new pinion nut, a pinion shim pack, marking compound with a brush and thread locker. Carrier bearings are not included.

Symptoms that point to the pinion bearings

• Whine that is loudest on deceleration or light cruise and rises with speed
• A clunk or delayed take-up when you go on and off the throttle, from pinion play
• Gear oil seeping at the pinion seal and slinging onto the driveshaft area
• Noise that began after hard launches or a gear swap done with reused bearings

How to confirm before you buy

Camaro rear noise can come from the half-shafts, wheel bearings or the module itself. Our guide to differential whine on acceleration vs deceleration helps separate gear mesh from bearing noise. With the car safely supported, check for pinion play by hand at the flange and look at the seal area. If you are replacing gears as well, the GM 8.5/8.6 ring and pinion kit buyers guide explains which parts each kit level covers.

Fitment

R8.6RPK is listed for the GM 8.6 inch IRS rear in the 2010-2015 Chevrolet Camaro and does not fit the ZL1 rear. Retail listings confirm it for the SS and the 2014-2015 Z/28. V6 Camaros and 1LE cars should be checked against the axle code before ordering, since rear axle options varied by trim. Match the RPO axle code on the glove box label, or send us your year and VIN and we will confirm. It is not for the solid-axle GM 8.6 10-bolt in trucks and SUVs, which uses different bearings. More axle parts are on our rebuild kits page.

Install notes

• Yukon's published chart for the GM 8.6 IRS (218mm) lists pinion bearing preload of 14-19 in-lb new (6-9 used), 6-11 thousandths backlash, 65 ft-lb ring gear bolts and 60 ft-lb caps. Use the gear maker's sheet if it differs.
• Seat the new races fully, set pinion depth with the shim pack first, then set preload. Tighten the nut slowly and check rotating torque as you go, because an over-crushed sleeve has to be replaced.
• Use the marking compound to confirm the drive and coast pattern before the cover goes on.
• If the carrier bearings are rough, the Motive R8.6RMK master bearing kit covers both sides, as does the Yukon YK GM8.6IRS overhaul kit. A clamshell bearing puller makes removal far easier.
• Refill with 75W-90 gear oil as GM specifies for your car and follow the gear break-in procedure before any track or drag use.

Does R8.6RPK fit the Camaro ZL1?

No. The ZL1 uses a different rear differential, and this kit is listed as excluding it. It is intended for the GM 8.6 IRS in the 2010-2015 Camaro, confirmed by retail listings for the SS and the 2014-2015 Z/28.

Are carrier bearings included?

No. This is the pinion kit only: Koyo inner and outer pinion bearings and races, pinion seal, crush sleeve, pinion nut, shims, marking compound, brush and thread locker. For both sides, use the R8.6RMK master bearing kit.

Do I need this kit to change gear ratios?

If the carrier bearings are healthy, this kit plus the new ring and pinion covers a gear change. The inner pinion bearing has to come off to reset the depth shim, so new pinion bearings and a new crush sleeve are standard practice.

What pinion preload is used on the GM 8.6 IRS?

Yukon's setup chart lists 14-19 in-lb rotating torque for new pinion bearings and 6-9 in-lb for used. Follow the specs that come with your gear set if they differ.

What gear oil goes in the Camaro rear?

Use the 75W-90 gear oil GM specifies in your owner's manual. After new gears or bearings, change the oil after the break-in period to remove early wear particles.