Update: Just installed the Vortex fan in our 2011 Montana no problems but a bit noisy kind of a faint grinding noise. Turns out our vent is a Ventline.
Mine made a funny noise and I was going to return it. I took it out and spun it by hand and could not hear the noise. I re-installed it and the noise was gone? I was thinking one of the blades must have been hitting something????