i dont have a sye for my xj, i just put 2 inch shackles on my 3 inch aal, am i going to need an sye, or can i get away with standard tcase and rear shaft?
what year is it? you could just drop your transfer case. Skyjacker makes one for a ZJ, and it is bigger then the one that they make for the xj. Before i put my longarm kit on that is what i ran, and it eliminated a lot of vibration.
another thing to think about is its not all about vibs, even with no vibs your still putting stress on the TC, over 3 in its a good idea to just go ahead and get one