Hi there, just wondering if you ever figured out what this issue was. I have the same problem, at low speeds when I'm going up or down my parking garage at work when I turn left or right I get a whining/grinding noise.
if it were the power steering I would think the issue would be repeatable when I turn the wheels full lock left or right since the pump is working its hardest then. but i have to be moving at low speed to hear it, and it also doesn't appear at high speeds (which I assume the road noise is just drowning it out)
I wondered if it were the diff or the wheel bearings/hubs.