GM 8.5in. 10 Bolt 3.42 O.E.M. Ratio For Use With 2.73 Up Carrier;Will Work In 8.6in. With 35-2022 Master Kit;10 Year Warranty;Computer Heat Treated 8620 Steel;Manufactured To O.E. Specifications;Double Shot Peened;Double Lapped G2 Axle and Gear G2 GM 8.5 Inch 10 Bolt 3.42 O.E.M. Ratio Ring and Pinion - 1-2021-342 1-2021-342 Ring and Pinions