All of the functions of the machine seem to work, but it periodically makes a loud rumbling sound, which I'm pretty sure occurs at the end of a drain cycle. The draining itself happens correctly. I'm thinking that whatever sensor there is to check the water level isn't working properly, and the drain pump runs too long, then makes the noise when it's running with no water passing through. The noise does end after a couple of minutes. I've also found that if I open the door, the pump stops, and then when I close it again it doesn't restart, but instead the machine continues its program. Can anyone tell me what should tell the drain pump to stop when it's cleared the water out?