2004 Chevy Tahoe VIBRATION

I recently had the front hub/bearing assembly replaced on my Tahoe. Since then there has been vibration in the front end and gets worse at highway speeds. I've had all the wheels rotated and balanced TWICE in the last week and yet the problem still exists.
Is there a chance the assembly is the culprit? I don't think it's the tires because they have approx 10,000mi on them and I rotated them at 5K. I don't want to go back to the shop until I have a better idea of what's going on. Thanks. -Jim