I bought a Kenmore dryer (Kenmore 70 series dryer, Model 110.66752500) like 4 months ago (used). But two months back now it started making a thumbing, squeaking noise. I changed the idler and rollers still it continue making the noise... but the only thing I observed the first time I opened (disassemble) the dryer was that I noticed the felt seal at the rear end is cut off at one end so I have to patch it back. This noise continues and recently I noticed blackish stains on clothes after its been dried and more so it takes a long time to dry clothes. Please what do you think could possibly be the issue with the noise and also the stains. And what can I do to get a lasting resolution.

Thank you.