Anyone knows why my tumble Dryer overheats and makes a grating sound?

MY Hotpoint TDL30 Tumble Dryer is making a grating sound when the drum is reversing. It is also overheating and causing condensation all over the machine. Clothes not drying.I opened it up and cleaned a lot of lint from it behind the drum and around it but the problem remains. I have noticed that the drum is a bit loose. Can you say what the problem is?