Tube had fallen and melted out of shape.

I removed the one screw that held the part in place. Since the exact replacement part was no longer made, I ordered the part closest to what I needed. It worked perfectly once I modified it a bit -- since it was plastic I was able to cut away some of the middle of the part so that it would fit properly. This just took a little more time since I didn't want to ruin the new part. I was then able to put the new part flush against the existing part in the dishwasher and screw it back together. Works just fine.