8.5" GM 3.90 Ring and Pinion Set

The USA Standard Gear ring and pinion set is engineered to meet or exceed OEM specifications for GM 8.5-inch and 8.6-inch axles. Each set undergoes rigorous in-house quality evaluation, including dimensional, material, and fitment testing, to ensure reliability and performance. This specific set provides a 3.90 gear ratio, ideal for applications seeking improved torque or towing capabilities, and features an 8.50-inch ring gear diameter with a 30-spline pinion and 10 ring gear bolts. This ring and pinion gear set is compatible with a variety of GM models. While specific year and trim fitment can vary, it is generally designed for GM 8.5-inch and 8.6-inch axles. It is important to verify fitment for your specific vehicle, as some sources indicate compatibility with 1973-1975 Buick Apollo and 1971-1989 models, and also lists fitment for 1999–2017 Chevrolet Silverado 1500 models. USA Standard Gear offers a 1-year warranty against manufacturer defects, providing confidence in your installation and long-term use.