Squealing sound from spinning drum

[Mozart1220]

 I just found this site because of a problem with our dryer. Everything seems to be OK except there is a constant squealing from behind the drum when it's running.  I have gotten to the motor and can spin it OK, but when the drum turns it sounds like metal on metal and in addition some small object is floating around. It sounds like a coin bouncing IN the drum but there are none to be found inside.
 I'm a fair "shadetree mechanic" but dryers are new to me and I don't want to take apart something I can't put back together.  

Model LDE9306ACE

[kellonnie]

you are going to want to check to see if something is stuck in the blower fan also check your felt guides on the back of the drum, also check your rollers

[magician59]

"Metal on metal" says felt seal and/or nylon glides. Invisible coins can be found under the baffles.

[JWWebster]

Check the drum glides (click pic to enlarge)