at 6.5" you should be on longarms, if your not then thats your biggest problem
also if you have the cv at the front diff pinion instead of a ujoint then that is probably it, they get toasted by anything more than 2" of lift
THat requires a yoke swap which can be somewhat detailed depending on your mechanical skills, you cant just unbolt it and slap a u joint yoke on
rotate the tires back one at a time and see iff it changes
V8 zj at 6" . Double tri rear and true 3 link front. Stretched to 108"