Motive Gear GM10-373 Ring and Pinion (GM 8.5" & 8.6",Style, 3.73 Ratio) Experienced installers know Motive Gear and trust us for the best quality and value for OEM replacement Ring and Pinions Engineered to the highest standards, every Motive Gear Ring and Pinion goes through rigid quality control processes in our in-house lab Street or Off-Road Use Ratio: 3.73