Yukon Rear Chromoly Axle for Jeep JL Non-Rubicon Dana 44, 32 Spline, 32.3" Long. Yukon 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 axle of unmatched quality and durability.