Damn. Uhm... The main pulley on the engine the turns the whole belt assembly could have a bad bearing, but that's the wrong area completely. I'm not overly familiar with the 4.0 either, I've got the 2.5. I'm trying to think of what's there in my cousins 95 cherokee, since it's relatively the same setup...But I'm pretty clueless
Sorry I couldn't be of more help- Hopefully someone else will get a chance to see this thread though. Alot of people on here are very helpful and alot more knowledgeable than myself. I usually just try to give any advice I might have, and keep the thread afloat long enough for someone with more experience to stumble across it. hahah.