First is it overloaded,if not possibly one of the springs or dampers has snapped or come loose.The drumm will be suspended in mid air by (probably 4) springs that keep it away from the body of the washer,if one is loose the drum will throw around inside the washer.If you can get the washer out and on it's back you will be able to look up inside it,it will be fairly obvious if a spring has come off or is broken,it's not hard to have a look.UNPLUG the washer first,good luck.
Rich, January 2019
