New Gears / New Whine/Whirr

So I posted recently that I just installed a new USA Standard 3.73 gear set, replacing my 3.23, last week. This was my first time doing a gear swap, but I felt pretty confident on final setup. Backlash was within spec, pattern looked good. A few days later though and I have a whirring noise coming from the diff. It's about the same volume as engine noise, but noticeable. Happens when accelerating and decelerating, if I had to say maybe a little louder on the accel. Doesn't make much noise at all when off the gas at speed (unless I really start slowing down).

Now, my beam torque wrench goes pretty high in in/lbs, so when I tightened down the pinion bearing I kind of eyeballed the 14-16 in/lbs as somewhere between 10-25. I just picked up a more fine, 0-80 in/lbs 1/4" wrench, maybe that'll help dial it in more precise. But could that be the cause of the noise? Or is it more likely something in the gear meshing, i.e. I screwed up the backlash reading?

edit: I'm about 100mi into the break-in.