I have a 99 cherokee xj and there is a squeal/squeak coming from one of my pullies(i think).

When I get it up to about 10 mph it starts to go away, but as soon as i let off the gas(even if its over 10) it starts squeaking, and no matter how fast im going when I accelerate it starts again. I know its not the belt cause when I put dressing on it the squeak stays!

Any help???