Very Bad Vibration

[mark4g63t]

I've double and triple checked. Everything is tight. Only things it could be would be driveshaft which looks to be ok, trans or t-case.
What in the trans or t-case would cause that tho?

Vibration only happens under acceleration but, not just wot. Normal driving around too.
Vibration gets more intense with RPMs/ speed
Vibration goes away as soon as I let off the gas and coast or if I push in the clutch it will also go away.
Can rev it and no noises are heard and nothing is felt.
With all 4 wheels off the ground and tires off and rotors bolted to hubs it still vibrates.
Can feel it in the steering wheel as well as in the butt seat.