My dishwasher (WDT720PADM1) recently quit washing (water would fill and drain but not spray). I replaced the pump assembly and it worked great again... for a week. Then it quit working just like before. The company I bought the part from is sending me a free replacement but I wanted to make sure there is nothing else wrong before I replace it again. Is it really possible I got a bad pump that only worked for a week or is something else going on?