My appliance guy came by this afternoon, disguised as a fire chief (he IS the chief in a nearby town - almost everyone out here has two jobs). The problem turned out to be a fan blade that had detached itself from its mount. Simple fix, no moving of the refrigerator required. I am SO relieved. He is concerned that the blade will come off again, so he will bring a new one by in the next day or two. Meanwhile we can reload the refrigerator. Since the fan is in the freezer behind the rear panel, I'm leaving that empty for him until he installs the new blade.
Who knew such a thing could happen? We are so lucky to have a great repair guy nearby. He sells new appliances as well, but I'd much rather repair than replace as long as the economics of doing so make sense.