Product review (1 stars): Worst component ever.
No offense to Amazon, they're just selling somebody else's junk. This part is a common component in some late model Whirlpool (and family) dishwashers. As others have already described before, it is designed to fail. You should expect to replace these every 6 months or so. Amazon is one of the cheaper places where you can buy this (incl. shipping). If you are considering another whirlpool dishwasher, plan to spend another $100-$200 over the life of the unit to cover replacing this part.

Three months later, the part still holds up - it is not breaking. However, this part comes in two variations, one with big wheels and another with smaller wheels. My original part had the bigger wheels, but the part shipped had the smaller wheels (even though they have the same part number). The first time around, I removed the wheels from the old part and put them on the new part.
The second time, I did not do it because I thought that by replacing the wheels I might have contributed to the part failing.
The problem is, that with the small wheels, the top drawer drops out of place and cannot be moved back into the rail, you have to wiggle and jiggle and shove it back.
Great design Whirlpool. This is going to be my last Whirlpool purchase for a while - i am very disappointed.