Grinding Noise. This dishwasher, the "quiet power II", makes quite a loud racket while in wash

Question

This dishwasher, the "quiet power II", makes quite a loud racket while in wash mode. I would call it a grinding noise. Sometimes, I can hit the front of it and it will stop, other times not so. And even sometimes, we can do two or three loads and the noise doesn't happen. (not often)