Model #KUDP02IRBT2, this tall tub dishwasher was making a noise that seemed to change from a ticking sound to a grinding sound as the wash cycle progressed. Still washing well for the customer, the problem was ignored, until they were tired of the noise and decided they wanted their quiet dishwasher back.
The wash pumps on these units are often the source of these unpleasant noises, because of a simple but effective design feature. Unlike many other dishwashers that use screens and filters to catch food particles and other random debris, these units use a chopper blade to grind up small bits of food or other organic matter allowing it to pass through the drain hose. These choppers spin at the same RPM as the pump impeller and when items that are difficult for the chopper to grind up get stuck, the result is usually a noise of some sort. Described as a fast clicking sound, the noise will usually occur from time to time as the chopper encounters these larger items. If by chance the item stuck in the chopper turns out to be something that cannot be chopped up, toothpicks, plastic items, or rubber bands for example, then the noise tends to last until the foreign object is removed. And every so often the wrong item makes its way into the wrong part of the sump and the result is permanent damage to the motor shaft.
When trouble shooting noises on these units, I will always remove the top of the pump and take a look at the chopper (the silver thing in photo above) to make sure it is not broken and nothing is stuck between the blade and the screen. If it is broken or clogged with food particles, replace the chopper. If the chopper looks good, clean out anything that may be in the sump as that could be the source of the noise. Once the sump is cleaned I will reassemble the pump and take it for a test. If the noise is still there, it's time to replace the motor. Removing the top of the pump, I looked for something that may be causing the noise. The chopper looked fine, and the rest of the sump was clean, so it looks like this unit needs a new motor. Because the pumps on these units have 5 year warranties, I replaced the entire pump and motor as an assembly which took care of the problem. With the unit now as quiet as it was before, I did a little customer instruction on what not to put into the dishwasher, and hopefully will prevent a noise like this from happening again.