Chromoly Rear Dana 44 Diff JK Rubicon Left Hand 32 Spline 31-1/4 Long D44 32 Spline 4340 JK Rubicon 31-1/4 Inch Left Hand Double Drilled Rear Yukon Gear & AxleYukon high performance axles are built with high strength 4340 chromoly, use superior production methods that include cold roll formed splines, and feature induction coil 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