I had a squeal develop after changing out the heating element. I checked all the bearings, rollers, glides, etc., and couldn't figure out what the deal was. Then I finally noticed that there were a few screws I had removed from the back of the dryer that secured the frame holding the rollers. The squeal was quite a chilling metal on metal sound. Your squeal could be a number of things. A few screws falling out would cause this as well.