Kenmore 200 Dryer scratching sound

Hello all,

I have a Kenmore 200 gas dryer and tonight I am hearing a vibrating type scratching sound when the dryer is running. It seems like its coming from the rear I took the top and front door down and I don’t think its the glides in the front seems like its coming from the rear right I believe. Any thoughts on what parts if I take the whole thing apart pulley off etc. to look to replace?