Motive Gear G875410 7.5" Rear Ring and Pinion for GM (4.10 Ratio) 8620 Steel Performance Differential Ring And Pinion Ratio: 4.10 Pinion Spline: 27 Ring Diameter: 7.5 Pinion Diameter: 1.438 Ring Gear Teeth: 41 Pinion Teeth: 10 Position: Rear