I first researched on AppliancePartsPros.com the availability of parts. It looked like all common parts were in stock ready to ship. I also found that APP had several helpful videos to show how to take apart the dryer and replace the parts. Other research indicated the most common problem is the drum rollers, but after seeing the videos I determined that not only the rollers but also the tensioner pulley could be bad and the belt too. So I bought all of these parts because I did not want to take the dryer apart and not have every possible part. The tensioner pulley was the main part that was bad, the bearings were very loose and making noises. But as I checked the drum rollers, 3 of them were not turning as freely as a new one. So I am glad I had the extra parts. So for anyone out there with a similar issue I would recommend just replacing all the drum rollers, the tensioner pulley and the belt. After I finished my dryer runs like new.
The videos said the job would be less than 2 hours, which normally it would be but with the dryer completely torn down, why not clean every possible area and part you can. So the job took closer to 4 hours with cleaning. One final note, from the factory I noticed that the plate the tensioner pulley is attached to is connected with a shoulder bolt to allow the plate to move freely with spring tension. This is all correct, but the plate to plate interface where the shoulder bolt is had a lot of wear marks and a lot of metal shavings under it. Also, the tensioner plate did not rotate very freely. I suspect that after years of service, that plate caused the wear and thus over time became less and less free to move. This probably eventually led to additional stresses on the bearings because more tension from the belt was being put on the pulley. After installing the new belt I noticed the old belt was quite stretched out. So, My final recommendation is to put a dab of high temperature grease on the tensioner plate so that it will have less metal to metal wearing.