I am just in the process of replacing my chopper assembly for the third time in as many years. We're going to have to be more careful about scraping the plates off. My dishwasher was making a horrible racket for the past couple of weeks. It turns out the chopper was broken and had deposited a couple of pieces into the end of the housing. I cleaned them out carefully and, using a flashlight, checked out the end of the shaft to make sure it was still okay. I then ran the dishwasher without the chopper, screen or lower wand, etc. in place to see if the racket was eliminated. Viola! Now I just have to wait until my new chopper assembly comes in. Just make sure you run the dishwasher empty because without the screens in place, you're just asking for trouble by getting the crap from your dishes wrapped up in the impeller.