A thumping sound (like sneakers in the dryer) started happening. We stopped using it so that it wouldn't get worse and potentially break more parts. Online research suggested rear drive shaft would be the problem. But also suggested while we have the dryer apart, would be smart to replace the belt and the slides/glides (green and white plastic tabs in front, attached to the door). We ordered all the parts from AppliancePartsPros.com and they arrived FAST.
It helps to have two people for this repair. The videos are really great. The hardest part to do is to uninstall and re-install the belt because it's all underneath the drum in a tight space that is hard to see. Study the video carefully to understand how the belt should be threaded and how to move the pully arm. If you don't, you may have a problem with the motor switch. This is a part that is against the pulley arm/tensioner. If it doesn't engage properly or if you damage it, the dryer won't run. This happened to us. When we reconnected everything the dryer would start briefly, but it wouldn't continue unless holding the start button down. We had to look up another video about that problem (found on another site) and learned about the switch. Had to take the drum back out, fiddle with the pully arm and get it reinstalled exactly right. Then, the repair was a success. Luckily we did not break the switch, it was just not aligned. So the repair took much longer than expected. But the steps are generally easy to follow and the tools are simple.