Front End Vibes - FRUSTRATED

I had Six States install 4.56 Yukon gears front and rear. The rear gears make a terrible howl on decel...that is another story. D30 front, D44HD rear.

I have a terrible vibe up front, sounds almost like the front pinion and ring are grinding each other to peices. Six states tells me the front end looks great, it must be something else. They removed both my driveshafts and balanced them with no change. It only makes noise and vibes when I am on the throttle or it is under load, the noise starts to get very loud at ~55mph. When I let off of the gas completely, the noise goes away up front, I only hear the rear gears. The noise is much quieter when I am up to freeway speed and cruising, but as soon as ANY incline or acceleration hits, the noise gets WAY loud. I was beginning to think I had a bad CV shaft up front, I just don't know any more. The vibration is with vehicle speed, something in the drivetrain.

I can feel the vibrations under my feet on both the drivers and passenger side traveling up the control arms....(Long Arm mounts are under my feet). This is my wifes DD, and she is very unhappy at the moment. I HAVE to figure out the front end vibes, they are not tollerable. It does't feel safe to drive at freeway speed. Any idea's?

99 WJ Limited 4.7 | 6.5" R