Carrier and pinion bearings, shims, crush sleeve and seal for installing gears in a GM 8.5 inch 10-bolt with 30-spline pinion, 1971-1984.
New gears in a GM 8.5 inch 10-bolt need new bearings, a fresh crush sleeve and a stack of shims under them, and hunting those pieces one at a time is how a weekend regear turns into two weeks with the axle on jack stands. The Allstar Performance ALL68521 puts the whole bearing side of the job in one box for the 8.5 inch 10-bolt with a 30-spline pinion, the axle under a long run of Chevrolet and GMC cars, half-ton pickups and SUVs. Buy it for a ratio change after bigger tires, or for a tired 10-bolt that howls on the highway and leaks at the pinion seal.
The 8.5 is an integral carrier axle: the pinion runs on two tapered roller bearings in the nose of the housing, and the carrier rides on two more bearings held in by bolted caps. Pinion depth is set by a shim behind the inner (head) pinion bearing, pinion bearing preload comes from tightening the nut against a collapsible crush sleeve, and the carrier is positioned side to side with shims between the bearings and the case, which sets both backlash and carrier preload. Every one of those dimensions changes when the gear set changes, so the old shims and sleeve cannot simply go back in. Allstar's spec sheet lists ALL68521 as the bearing version of its 8.5 10-bolt kit, with pinion and side bearings, pinion seal, pinion depth shims, adjustable carrier shims, crush sleeve, pinion nut, a one ounce tube of silicone, gear marking compound and ring gear bolts. Allstar also sells a shim-only kit, ALL68621, for jobs where the bearings are staying.
First, make sure the noise is the axle. Coast at the speed where it is loudest, then roll on and off the throttle; our whine on acceleration versus deceleration guide walks through what each pattern means. Second, make sure it is an 8.5. GM built 7.5, 7.625, 8.2, 8.5 and 8.6 inch 10-bolts, and from behind they look much alike, so measure the ring gear or read the axle tag rather than trusting the cover. The GM 8.5 and 8.6 ring and pinion buying guide covers the identification steps and ratio choice, and the GM 8.5 rear end problems guide covers what usually fails.
This listing is for the GM 10-bolt with the 8.5 inch ring gear and a 30-spline pinion, shown for 1971-1984 cars and light trucks. Allstar's own application chart is broader and lists it for 8.5 inch 30-spline passenger car and light truck axles from 1970 to 1998. Bearing sizes changed across that span, so the safest check is to read the numbers on your old pinion and carrier bearings and compare them with the kit, or send us your year, model and VIN before ordering. The 1999-and-later 8.6 axle under full-size half-tons is not covered here. More parts for this axle family are in our rebuild kits category.
Fill with 75W-90 GL-5 gear oil, adding friction modifier if the axle has a clutch-type posi, then break the gears in gently and change the oil early. Our ring and pinion break-in procedure has the mileage plan. Pair the kit with a gear set such as the GM 8.5 3.73 30-spline ring and pinion or the USA Standard 8.5 3.73 set. If the yoke seal surface is grooved, replace it with the Yukon forged 1350 yoke so the new seal lasts, and a side bearing puller set makes removing the old carrier bearings far easier.
| Part number | Allstar Performance ALL68521 |
| Fits | GM 10-bolt, 8.5 in ring gear, 30-spline pinion, 1971-1984 cars and light trucks |
| Includes | Pinion and carrier bearings, pinion seal, pinion depth shims, carrier shims, crush sleeve, pinion nut, silicone, marking compound, ring gear bolts |
| Warranty | 90-day limited factory warranty |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes. It is the bearing version of Allstar's 8.5 10-bolt kit, with pinion and carrier bearings, seal, shims, crush sleeve, pinion nut, silicone, marking compound and ring gear bolts. The shim-only version is ALL68621.
This listing is for the 8.5 inch 30-spline 10-bolt. The 8.6 shares gear sets with the 8.5, but its bearing kit is listed separately, so match your bearing numbers or send your VIN before ordering for an 8.6.
Both have ten cover bolts, so the cover is not proof. Measure the ring gear diameter or read the axle tag. An 8.2 needs its own parts and does not share gears with the 8.5.
No. A crush sleeve only collapses once to set preload, and ring gear bolts are stretched by their first torque. That is why this kit includes both.
Use 75W-90 GL-5 gear oil. If the axle has a clutch-type posi, add friction modifier unless the oil already contains it, and change the oil after the break-in miles.
Plan on an inch-pound torque wrench for pinion preload, a dial indicator for backlash, and a press or side bearing puller to remove and install bearings. The marking compound for checking the pattern is in the kit.
