Dryer make a low pitched squealing noise when it first starts for about 20 seconds. Rear bearing is fine. Changed rear bearing sleeve. Changed front drum glides maybe a couple of years ago. Still getting noise sometimes only for 5 or 10 seconds on startup. Could the belt be worn and slipping when it first starts?
You will have to open it up to see what the problem is.
I doubt it is the belt.
Could be that the drum glides are gone again. Also check the idler wheel.
May even be the motor bearings are going.
Opened it back up to check again. As the idler wheel was spinning the arm it is attached to was vibrating. I think the wheel hub was worn a lttle and not spinning smoothly. Changed it and seems to have done the trick