I've always trusted Appliance Parts Pros so I knew where to go on the Internet for expert help. I always get the right part the first time and if I'm unsure if it's the correct part I just send them an email.
I watched their video on how to replace the drain pump on my dishwasher. The important thing to remember when putting the new drain pump on is to make sure the rubber seal is completely seated in the center by applying equal amount of pressure around the new part to make sure it is well seated and to make sure that the two tabs of the pump housing on the dishwasher get seated inside the connectors of the new drain pump . It will be hard to turn by pushing in and turning counter clockwise at the same time to properly install the part, but you can do it. Watch the video a few times until you understand the process. Once the drain pump is on, rock the new drain pump you just installed back and forth a few times to make sure that it is properly seated and the tabs are secure. If it's not seated properly it will come off on one side. Just try it again. I turned my dishwasher on its side for an easier repair.
My drain pump blew off and flooded my kitchen when I did a test run . I just made for sure to press harder on the new part to make sure it seated properly and the tabs on the dishwasher housing were inserted securely into the new part. This fixed the problem.