The reason your dryer is making a grinding noise is because there is so little room between the drum and the cabinet, that as it heats up and all the metal expands the drum is rubbing on the backplate and making a scrapping noise.
The fix this problem you will need a lot of patience as it involves loosening the screws in the backplate and twisting the cabinet slightly then tightening the screws. It will probably take 4 or 5 goes to get it right.
neville
January 2007