After using our 31ul for a couple of months many strange noises went away. Some had to be repaired. We had a vacuum line under the dash that was kinked, made strange noise and messed up our heater/defroster controls. We had a water line under the sink that kept banging on the cabinet, got it rerouted and all is well. Now when I hear the sound of broken dishes I know not to worry because its only the glass plate in the micro wave out of its track again. My wife is too short to remove it and I always forget to. My summer project is to lower the microwave, failing that the wife will be put on the Rack.
Bob