This photo of the stub shafts shows the standard TJ (left) and the JK Rubicon (right). In addition to larger U-joints, the JK Wrangler Rubicon's stub shaft has increased spline count and shaft diameter compared to the standard TJ. Currie Enterprises is working on a TJ Wrangler front-axle upgrade that will allow use of JK Rubicon U-joints in the stock TJ front axle, whether it's a TJ Dana 30 or a TJ Rubicon Dana 44. The upgrade retains the 5-on-4.5 TJ wheel-bolt pattern. Bigtime strength and worry-free wheeling are sure to be the results. Stay tuned.