I have a brand new one of these in a box. Took it out to see. Definitely no sounds. Spinning it by hand is whisper quit and movement is smooth. Although it pulses at very slow rotation, as yours does, because its just passing between the magnets I believe. My guess is that, since it seems to spin well, there is just something a little out of tolerance inside the motor case. If the shroud is cut to fit and there's no returning it, you might as well open it up and take a peak.
Good luck
