I have a 25ish year old Kenmore 90 series dryer that was buzzing instead of starting sometimes, and sometimes not starting at all. The drum was really hard to turn. I found this thread and feared that my motor was dead, but I pulled the machine all apart to have a look. I didn't find anything stuck in the motor and the fan seemed to rotate just fine. For me the problem turned out to be that one of the front "wheels" that the drum sits on was really hard to turn. Since I figured that it should spin freely, I removed the gunk from the wheel, lubricated it, (I used 3-in-one oil, but I am not convinced that was correct) and it is back up and running again!