I'm new. Did a search for this problem and found your site. a few relevant questions asked on this topic already but I thought I might could add a bit more information to find out what the problem is. if you ever have a computer problem I’m your guy but these mechanical gadgets are above my head.
After a long six month road trip, I noticed the first night back home our dishwasher (Kenmore Ultrawash, only about 8 years old, awesome machine) made a loud humming noise. Buzzing, Humming, like a bumble bee about four feet long. After a time it quit. I didn’t notice when it stopped. There were a lot of things going on in our household and I just suddenly realized one day it had stopped before I’d had a chance to look into it.
Tonight I heard a something that sounded like a vacuum seal closing, then the humming started. I thought something (valve?) had closed before it should have. I opened the washer, removed the lower arm and checked for any debris in the trap. The top of the filter screen is clean and there isn’t anything in any of the passages I could see. Each time I close the washer door there is a sound like something in a garbage disposal, only plastic. Thumping, clumping, bumping around, then the humming. After a moment the racket stops but the humming continues, like a plastic fan blade hitting something it shouldn’t. I open the door, close it, the thumping, banging around begins again and then calms down when the humming starts.
Something is definitely in a rotating something somewhere only I have no idea where to even start. I can build a computer from parts but when it comes to things like this I’m a little in over my head. I’d appreciate any suggestions. I can use a screwdriver so I’m not totally useless.

Thanks.
RR