Furnace making unusual noise

[decodancer]

I've had my share of furnace issues and had to replace the squirrel cage recently due to mice but this is something new. It is working fine, coming on, heating and shutting off as it should. It sounds different the last few days though. Kind of MMMMMmmmmm. MMMMMmmmmm strong then weak hum over and over and louder than usual. No squeals or squeaks at all. I just got back from a trip so wonder if that has something to do with it. I'm a fulltimer in upstate NY and am hooked up to a large tank now though this started while I was running on my onboard tanks. Any input. Is appreciated. Thank you, Kathleen

[Skip426]

Did you have any problem removing the squirrel cage from the motor shaft?

Could you please add info on your furnace manufacturer and model and the age of the unit.