The supply tube to my middle spray arm is rotting out so I ordered a new one. It is comprised of three parts, each of the two ends and a middle flat tube connecting them (the middle tube is what’s failing). The new version comes as a whirlpool improved replacement kit (with a one piece tube plus the spray arm, bushing, and screw).
Link to diagram http://www.appliancepartspros.com/partsearch/model.aspx?model_id=238632&diagram_id=20724#d20724
The upper rack design is such that one side is lower than the other (to fit tall glasses). And the new tube (where the spray arm connects) lifts the spray arm about an 1/8" higher and the so it hits the bottom of the rack.
The kit does not come with a top mount. The one I have "fits" fine. Possibly a new one corresponds with the new arm kit to lower the spray arm. I don’t know.
I contacted the chat person and they don’t know of any new parts of the old style.
Any ideas? The dishwasher is in wonderful shape except for this one part…