I've got a problem with my washing machine. After a week or so of running it with the front panel off to visualize what's going on, here's what I've found. The motor comes on as it should during the spin cycle. However, periodically, though not every time, the motor pulley will spin, but just slips around the belt. If I manually move the belt, and all the connected pulleys, then turn it back on, it works for a few loads until it starts slipping around the belt again.
This explains why the thing smells of rubber when it fails. But the belt is intact. What would cause it to slip at the motor pulley?