Product review (2 stars): Part is fine, but impeller doesn't fit older Whirlpool, despite correct part number.
The impeller does not fit an older (2003-ish) dishwasher.  This, despite entering the exact model number and being told this is the right part.  The shaft on my motor is too large to fit the impeller's threads.  I didn't measure, but I would guess the motor shaft is 5/16" and the impeller is 1/4" or close to it.  If you've got your motor apart, take that into consideration before ordering.

I lucked out, as I really only needed the seals -- my old impeller was fine, so went back into the machine, and my leak is gone.  (knock on wood!)  For some reason, the seals are hard to find without the impeller, and cost more that way.  Go figure.