I disassembled the dryer and removed the drum. Inspection of the 4 drum rollers indicated that one of the rear rollers was defective (the shaft was scored and the roller was unable to move freely on it) I decided to replace all 4 rollers (which come with the mounting shafts), along with the idler assembly for the belt. I would have replaced the belt as well but it was unavailable at the time of my order and we needed to get the dryer working ASAP. This completely fixed the issue and the dryer sounds like new.