I have a Ruud UGFD high efficiency 75,000 BTU furnace, installed in November of 2005. The furnace it replaced (1960 vintage) had tiny little "bowls" above the fan bearings, that you could put oil in.
I only looked at one side of my fan while I was replacing the filter, and couldn't see any recepticles for oil, nor zerks. (I couldn't see the other side.) I did see what looked like a set screw that kept the fan from sliding off its shaft.
Are the fan bearings sealed on this model? Is there any way you can lubricate them, and should you attempt to?