Felt drum seal, idler pulley, dryer belt and rear drum roller support kit. The problem was probably the felt drum seal or the roller support kit. I replaced all items while I had the machine taken apart. No need to guess and do the work twice. This unit is about 21 years old and this is the first time any of these repairs/replacements were performed. I'm going to ride this dryer as long as the cabinet is intact and the parts are available!!