Chromoly For GM/AAM 11.5 Rear Differential 40.25 Inch Long 11.5 AAM 2011+ GM Full Float 4340 Rear (34.0 Inch - 40.25 Inch Cut To Length) (8x3.818 Inch )/ 97mm Bolt Pattern Yukon Gear & AxleYukon performance axles are built with high tensile strength 4340 chromoly, use superior production methods that include cold roll formed splines, and feature advanced heat treating to create an axle of unmatched quality and durability. Yukon high performance axles are built with high tensile strength 4340 chromoly, use superior production methods that include cold roll formed splines, and feature advanced induction coil heat treating to create an