Long story short...I found that the fan motor rubber bushing (that connects the fan to motor shaft) must have worn enough that allowed the fan to vibrate during a higher RPM. I removed the fan and then removed the rubber bushing. After I removed the bushing, I cleaned the end of the fan surface. I cut 3 one inch pieces of electrical tape and covered the bushing hole. I used a razor blade and cut the rubber bushing hole out. It wasn't perfect but just good enough to get the bushing back in. This took care of all of the vibration/noise I had.
Troy, January 2013
