Ok, I tore into this problem this weekend. It never ended up being the hub assembly/bearings. I ended up swapping the front tires and for some reason, I cannot explain....but it is quiet as a church mouse now. I did ended up swapping out the brake rotors because one was very rusted and pitted. My Hummer came from Sioux Fall South Dakota, and I can see it hit the streets a lot while they were salted in the winter.

But the growl/grind did not go totally away until I swapped tires. Drove it all weekend and it is nice and quiet turning both ways. Weird.

 

Sounds like a steering ball joint is worn, or it could be a defective wheel bearing - if you jack the wheel up off the ground and put it on an axle stand, you can then shake the wheel with a hand top and bottom, and then side to side.