Water is not circulating through either the lower or upper arms of my Sears Elite dishwasher, Model No. 665.15982990. I can hear the pump running but it appears it is just recircing water around the bottom with none being forced up in the spray arms. It fills and drains normally, I removed and cleaned the strainer on the bottom. While putting it back together, I can't see what holds what I'll call the upper pump housing from the lower. I don't see any broken parts. Could this be the problem?