3.08 12 Bolt GM Pass

The Richmond 3.08 12 Bolt GM Pass ring and pinion kit is a precision differential gear set designed specifically for GM 12-bolt rear axle assemblies. This kit is ideal for vehicle builders, restoration specialists, and powertrain technicians looking to upgrade or rebuild their GM 12-bolt differentials.

Engineered to OEM specifications, this 3.08 ratio configuration provides a balance between drivability and fuel efficiency, making it suitable for street-driven vehicles. The kit features a 30-spline pinion gear paired with an 8.875-inch ring gear diameter, which is the industry standard for GM 12-bolt platforms. This gear ratio helps reduce engine load during highway cruising.

Common applications for this ring and pinion set include 1960s–1970s muscle cars, trucks, and performance vehicles where original equipment specifications are being modified or restored. Proper installation requires attention to setup procedures, including backlash adjustment and bearing preload, to ensure optimal performance and longevity.