Three potential causes of strange noises coming from a clothes dryer include coins or items stuck in the drum baffle, a jam in the dryer's blower housing or a drum rub. A drum rub involves a scraping sound as the side of the dryer rubs against the rotating drum.
A rattling sound may be an indication that the dryer is not placed on a level surface, and it is shifting when in use. Coins, hard objects or even buttons within the interior of the dryer can cause rattling sounds, too, as the clothes are tossed around.
A thumping sound can occur if the support rollers of the appliance have flattened where the rollers and dryer drum connect.