Not cleaning well and noticed a periodic groaning sound during wash cycle. Upon further observation, noticed that when it was groaning, no water was being pumped. If I open the door while it is groaning, the arms are not turning & not water is spraying. It does pump sometimes. It is almost as if the pump looses its prime or cavitates and then recovers. It is probably pumping about 50% of the time. Water level seems OK. Have disassembled multiple times looking for problems. Filter and screens are clear. Pump rotor looks fine. Even disassembled the motor to check bearings & windings. Motor still looks new (dishwasher is about 6 years old). Ran all of the self tests - OK. Motor current draw is around 1 amp and remains steady even during the non-pumping times. As near as I can tell (I can not see the motor shaft), the motor is still running while it is not pumping (still vibrating, humming and drawing power). Current on start winding is 0 after startup. If a winding was intermittent or the start capacitor was flaky, I would have expected some variation in current draw.
I am at a loss as to what is going on. I'm not ready to put in a new $150 pump assembly without a better diagnosis.
Dishwasher Motor Part # 6-919922