These spider gear kits are the ultimate budget-minded high-quality option for your rear end. The meticulous production process includes procuring raw materials from the best reliable sources, forging the materials under strict supervision to ensure proper chemical composition, broaching, chamfering, heat treatment, shot blasting, grinding, and a final inspection. Spider Gear Kit. Fits GM 8.6" open differential with 30 spline axles. Includes (2) side gears, (2) pinion gears, (2) side gear thrust washers, (2) pinion gear thrust washers, (1) cross pin shaft, and (1) cross pin bolt.