Chromoly Inner Front For Dana 44 Diff 30 Spline Left Hand 18.91 Long 18.91 Inch 30 Spline Inner Left Hand 4340 D44 Bronco & F150 297X 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