The XJ 30 will bolt right into a TJ the difference will be the gears as most XJ's were built with 3.55 gears and TJ's had 3.73, 3.07 or 4.10s depending on engine, trans and other options. So as long as the gears are right you will have no problem. The hubs would need to be changed if the TJ is a 99 or newer because they had changed the spacing of the hub to rotor when they went to the full cast rotor, or use the XJ rotors but the full cast rotors are better they were alsoo installed on 99-01 XJ's but the 00-01 XJ Dana 30 is a low pinion like the TJ. The TJ LP and XJ HP gears are not interchangeable.