GM Open 8.5 Rear 30 Spline Spider Gears

The Motive Gear GM Open 8.5 Rear 30 Spline Spider Gears kit is a complete differential spider gear assembly designed for GM 10-bolt rear axles. This component set includes all hardware, pinion shaft, spider gears, and washers needed for open differential function, making it essential for both original equipment replacement and performance drivetrain builds where standard traction characteristics are required.

The 30-spline specification ensures compatibility with GM 10-bolt axle housings commonly found in light-duty trucks, SUVs, and performance vehicles from multiple generations. The open differential design provides equal torque distribution to both rear wheels during straight-line acceleration while allowing speed differentiation during cornering—the standard behavior expected in street and light-duty applications. The complete kit format eliminates sourcing individual components and ensures proper mesh geometry when assembled correctly. With a total weight of 4.5 pounds, this assembly integrates into the differential carrier without requiring modifications to existing mounting points.

This kit serves technicians, rebuilders, and vehicle owners performing differential service, repair, or restoration on vehicles equipped with the GM 10-bolt rear axle platform. It is commonly used during axle rebuilds, after worn spider gears require replacement, or when returning a limited-slip or locking differential to standard open configuration. Proper installation requires knowledge of differential assembly procedures and correct torque specifications for ring gear bolts and side bearing preload.

The GM 10-bolt remains one of the most widely serviced light-duty axle designs in the market, with broad application across Chevrolet, GMC, and other GM vehicles spanning several decades. Availability of quality replacement components like this spider gear kit helps technicians maintain fleet vehicles and extends the service life of existing drivetrain assemblies without requiring complete axle replacement.