Dishwasher made a grinding sound - very loud. Did a poor job cleaning.

I took the lower pump assembly apart to find the problem. The biggest challenge was figuring out how to remove the cover. In the center, the assembly is held together with a round plastic nut about 1.5 inches in diameter - simply rotate it counter-clockwise to remove. I then removed the pump housing and found the impeller broken in two and the disk that was supposed to be attached to the top of the pump housing broken off. This was causing the noise and greatly reduced efficiency of the pump. I replaced the impeller and upper pump housing (bought the gasket too since it is hard to remove the old one) and put everything back together using the diagrams provided on the site. While many rate this repair as "easy" - it is only after you figure everything out! If you knew exactly what you were doing, the project could be done in 10 minutes. I had to study the diagram and it took me some time to disassemble, figure out what was wrong, read posts, order parts and reassemble. I also replaced the handle which had broken on one side which was simple. Part select is outstanding - I've used this site for my fridge, oven and now dishwasher and have avoided expensive service calls. If you are technically inclined and patient, you can repair your own appliances.