I purchased a Whirlpool GU3600xtvy dishwasher and it worked well for 3 months. A few days ago during the cycle there was a clicking or rattling noise, and now it does not drain completely. There is about an inch of dirty water at the bottom at the end of the cycle. Pressing Cancel/Drain causes the pump to run (it sounds fine), but pumps very slowly... we need to press "drain" about 10 times for it to finally all be drained. I do not have an air gap, but the drain hose goes up to level with the top of the dishwasher before entering the drain pipe. Any ideas? Whirlpool does not stand behind their warranty as I brought this product across the Canada/US border.