The bottom plastic ring in the drum is an air tank. Water can, on some machines, seep into this air tank and prevent it from rising up in the water thus preventing the drum driver from engaging. To fix simply undo the the top panel, then the top ring from the drum, then the agitator. Now just pull up the stainless steel drum with the top and bottom drums made of plastic. You will hear water sloshing if the air tanks have been compromised. Simply poke a small hole into the tank, near the bottom for the bottom tank and top for the top tank. Allow bottom tank to drain, this may take some time, depending on the size of the hole. When the bottom tank is empty simply turn drum upside down to drain the top tank. Plug the holes you made with silicon and reassemble your washer.