Whinning from gears comes from two sources that I know of. One is lack of
oil, which doesn't sound like your problem, and imperfect alignment, which does. Each
gear tooth is cut to roll against another, with teeth being a different shape depending on the number of teeth in the gear. If that alignment gets off a bit, it whines. You can hear the same no-quite-fitting whine in reverse gear on your car, since cutting a gear to fit in both directions is apparently a problem.
So, the retorque your bolts
advice is right on.