Allstar Ring and Pinion Installation Kit for GM features a ring and pinion installation kit that fits GM 12-bolt differentials with 8. 875 inches ring gear used in hi-performance passenger cars. It is a complete kit containing all the hard-to-find individual parts for a quick, trouble-free installation. kit includes: pinion and side (carrier) bearings, pinion seal, pinion depth shims, adjustable side (carrier) shims, crush sleeve (spacer), pinion nut, one ounce tube of silicone or gasket, gear marking compound, and ring gear bolts. It is backed by a 90-day limited factory and sold as one complete kit.