Diagnosed the source of the leak to the small rubber seal around the diverter valve shaft motor. This is probably a $3.00 seal, but unfortunately, it is not available as an individual part anywhere. I had to buy the entire sump assembly. The part arrived and was exactly as described. The installation took about 1.5 hours, but only because of the need to adapt a different style of hose clamp to the main pump lines. I used a common screw-type hose clamp versus the one used crimp-on type supplied at the factory. They worked just fine, but I found by cutting the inner hose clamp retention ring on each end of the hose, they fit and clamped better. All said, it was probably best to have replaced the entire sump assembly, as something else would have failed later by just replacing the single seal. Tip: if you perform this repair, it is important to note the rotational position of the sump in the washtub hole. This is because you need to align the diverter valve manifold on the inside of the unit with its mating connections to the upper and lower dishracks.