GM 8.5 10-Bolt Ring and Pinion Installation Kit, Allstar ALL68521

Allstar Performance ALL68521 is a full ring and pinion installation kit for the GM 10-bolt with the 8.5 inch ring gear and 30-spline pinion, as used in GM cars and light trucks from 1971 to 1984. Check your ring gear size and pinion spline count before ordering, since the 8.2 and 8.5 10-bolts look alike from the outside.

In the box: pinion bearings, side (carrier) bearings, pinion seal, pinion depth shims, adjustable carrier shims, crush sleeve, pinion nut, a one ounce tube of silicone for the cover, gear marking compound and ring gear bolts. It covers the hard-to-find pieces so the job does not stall halfway through waiting on a shim or a bolt.

Use it for a gear ratio change or to freshen a 10-bolt that has worn bearings and a weeping pinion seal. Set pinion depth first, crush the new sleeve to your preload spec, then shim the carrier for backlash and preload and confirm the contact pattern before closing the cover.