So there is a area on our gas furnace that is called a squirrel cage, and i did some researching late at evening because our gas furnace was making an terrible thumping sound. I have deduced that the squirrel cage is the reason for our noise, however the motor could sound almost prefer it is bouncing if the squirrel cage bearings are out, but online said to put a sturdy piece of styrofoam under the cage to stop it from moving; First, I did not prefer that the repair was not to actual repair the system, however just adding something around the apartment to stop it! Next, I did not prefer that I had no idea what bearings or a squirrel cage was, and a squirrel cage is the type of fan that can be found in a gas furnace. It moves the air through the gas furnace as well as this is what heats your home. The reason it has such a stupid name is that the fan looks prefer a hamster cage. Apparently it is a lot of little fans working together to transfer the air in as well as out of the gas furnace, and most people just refer to it as a blower. The bearings or pieces holding it all together can prematurely wear out as well as allow it to bounce around. How the bearings can wear out is the blower is unbalanced or the heating system has warm to the point that the bearings could just not take it anymore. Either way, getting modern bearings does not sound so expensive. I would way rather do this than add foam under a piece in our gas furnace.