My 96 cherokee just threw a belt. I was sitting at a stop light and went to pull away and i felt it jump and then it started squealing. I kept going and when i hit the brakes the noise went away but then I lost power steering. Then I noticed it
overheating. I pulled over and popped the hood, and the belt was wedged in the fan and completely off every pulley. Any ideas what caused this? It all happened within a 2 minute period. I've never heard of a belt just coming off when it wasn't broken.

 

your belt needs tension to stay on.

So your idler pulley might be loose or you have to look at the power steering bracket.

You should have a diagram in the engine bay, which will explain how it goes back on.

 

check your water pump as well, when they get really wore out the bearings around the shaft break down and it gets tilted by the preassure from the belt tension. Just grab the pully and wiggle it from side to side, if it moves, you need to replace it.

 

What you have is your Vibration Dampener (the main pulley attached directly to te crankshaft). Is starting to separate. This is a common problem with highmileage 4.0 motors. You'll need to get another. This is one time I recommend buying new over a JY donor. I bought mine at Autozone. I believe it was around $80.

 

X2 on checking the balancer.......but you may get lucky and just have a work out belt.

 

It looks like what happened is the fan somehow wedged itself into the radiator, it looks like this happened before the belt slipped and is what caused all the problems. I got the fan freed up and belt it back in place, hopefully this solves the problem. The only thing i can think of is something got jammed into the fan (trash, bird, whatever else) and made this happen.