Success on mine! It used to squeak all night, so bad that we would rather be cold.
Removed the grate, unscrewed the unit from the wall, disconnected the gas line (after turning the propane off lol), then had to disconnect 3 sets of wires - lucky for me, the wires had already been cut, so it was just a matter of unscrewing the twist-on connectors.
At this point, I had to reach back and grab the unit from the bottom and do a few heave-ho's to get it out. Took it into the garage, and just started removing screws and hose clamps. Dead bees and wasp nests came out en masse! Located the fan, and sprayed wd40 into the shafts, then put it all together. Reversed all steps, installed it back into the rig, and no more squeaking!
Thanks to everyone who contributed on this thread, you saved me!