I have a ComfortMaker RPJ II that's about 10 years old. Recently it started making a noise and lately I could hear what sounded like a vibration when the fan started and stopped. Yesterday I climbed into the attic and took a look. When I rotate the blower fan by hand I can hear a clicking (tin sounding) noise like one of the blades is hitting something and when the fan startes it is obviously vibrating until it gets up to full speed. The same thing happens when it shuts off. It looks very difficult to pull the fan and motor. Any suggestions will be appreciated.