The JK Dana 30 uses 1.16-inch, 27-spline shafts with 760X-sized U-joints. The Rubicon 44s run 1.31-inch, 30-spline shafts with a larger 1350-size joint. Dynatrac’s McGean warns the Rubicon Tru-Lok electric front locker employs an offset centerpin, so unique-length axleshafts are required if retaining the stock locker. Some aftermarket shafts don’t address this issue, so check against the stock shaft length before you plunk in your new units. Furthermore, McGean warned us the cost of a replacement Tru-Lok has skyrocketed to $1,800 MSRP. If you buy aftermarket shafts to work with your Tru-Lok you can’t use them with an aftermarket locker, so if gnarly wheeling with big tires is your forte, you may want to consider upgrading the locker when you buy your shafts.