I have the dishwasher apart. The chopper assembly is on the ouside i.e the side I can see with trhe screen behind. This appears backwards to me I had a repair man a while ago and i wonder if he put it in backwords. I have a memory of replacing it several years ago my self and I think it was the otherway. Am I dreaming
Could find no info using the given Model Number perhaps you can find a picture of how it goes together here
http://www.applianceaid.com/dishwash.html
Your dishwasher was made by Whirlpool.