Nine times out of ten it's a broken belt, but there are other factors that can cause this problem.
- Broken belt -- Replace with an identical belt. Line up
the new belt with the markings on the drum from the old one. Wind it
around both the motor pulley and the idler pulley.
Roller could be bad -- Underneath the tumbler is a roller that the
tumbler sits on. It may have become too worn to work properly and may
need replacing. Replacing it is simple - just remove the tumbler to
gain access and then remove the retaining clip on the roller and slide
it off. Reverse the process to install a new one.
- Motor or idler pulley could be bad -- Check the pulleys to ensure they're still in working order.