My lens (Samyang) keeps only very small amount of noise when I turn my focus ring. I have to put my ear to lens to be able to hear it. This noise is more like very smooth and silent.
If you also have these aperture problems then it might be better exchange that lens to new one. Mailing back and forth really isn't that much fun, but hopefully at the end you end up with properly working lens.
Yea, I was trying to convince myself that maybe it just needs a "break in" period, but that doesn't make much sense 
Oh well, I'll take it to the post office on Monday.























