I have an 08 patriot sport. It's a 2.0L 2wd (it's at 60K). A couple months ago we went on a road trip it's about 300 miles each way on the interstate. On the way back I kept hearing a loud consistent grinding sound (not the oh crap my tires is about to fall off kind of grind just a steady almost humming sound) that got worse with acceleration (it sounds super loud inside the car but you can barely hear it outside of the car). It has been about 3000 miles since this started. We had the tires replaced about 1000 miles ago and the mechanic said it sounded like it could be the wheel bearing. There is NO wobble in the tire and there is no pull whatsoever though, so I am doubtful that this is the problem. The sound gets louder on acceleration and slowly quites on decel. Any suggestions?