99002281 check ball is really small dia, like 1/8". Like the one person was asking no way will it stay under the gray part where it looks like it should go. Part number 39 is not available. The ball that would fit under in that indention would be about 3/8" dia. When I took it apart I found the small blue one like in your picture of the part. I just don't know where it goes. Help?
Answer Budweiser, Part #39 is the check ball, there are two different sizes 99001798 and 99002281, depending on series/serial number. Once you have the drain cover 99001795 removed, You should see the indentation for the check ball molded into the outer pump housing. You'll need to install everything below the drain cover first. then is you use some water soluable grease, and put a dab in the indentation, set the check ball in the grease, and then install the drain cover, you may find that a bit easier to work. Once everything is installed, when you test the dishwasher, the water will remove the grease, and everything will be fine from there.