You specifically need a Rubicon driveshaft then. Standard TJ & LJ driveshafts are different from Rubicon driveshafts in that they have a slip-joint and they use an incompatible 1310 size u-joint. The Rubicon doesn't use a slip-joint and it uses different size u-joints that vary in size by being for 2003-2005 vs. 2005-2006 Rubicon.