re-gearing problem

I had a 4 wheel drive shop completely rebuild an 8.8, but I checked the gears and have a problem with the ring and pinion binding when I spin it as if it were moving forward until I let pressure off. If I spin them backward, they don't lock up at all. I have it hanging on saw horses with the pinions pointing toward the ground. Could its postion on the saw horse be the problem or did the shop not install the gears right?

I would take it back, they should bind any.

He meant they should not bind any.