I just replaced the old belt with a new one and now it seems to squeal really bad when i start it up. With that squeal i also get a drop on the volt meter. It runs for 30-45 seconds and then stops squealing and the voltage goes back to normal then its fine. Anyone have any suggestions?

 

Your belt is to loose. You should go to the auto parts store and pick up a belt tension gauge. The belt on the 4.0 need to be really tight. It is hard to believe that they have to be so tight. Once you tighten it you shouldn't have any more squealing.

 

the new belt may have something on it, making it slip and squeal for a bit.

 

I would suggest loosening the idler pulley, turn the adjuster bolt a very small increment (to tighten the belt) and re-tighten the idler pulley. May need to repeat several times. The goal is to have the belt as loose as possible without squealing. The looser the belt, the less load on accessory bearings.