Hmm, don't know much about the dryers... I think, the drum is carried by rollers and these have bearings and these get worn over time. If you just take the font apart, there will be 2 weels a the front and these need a replacment, I think. look at the vdieo I posted. A condensor modell, but will be quiet similar to this. If there is a metal squeking noise, the felt bearing (i think there is one at the back of the drum?) may be gone.
The bearings on the washer are easy to diagnost which bearing is gone: Take the washer top off, pull the belt off and then turn the drum. If the noise is still there, your drumbearings are shot. If not, the motor bearings need replacment.