Driveline vibrations help

I just replaced my carrier bearing and middle u joint. I put the middle yoke joint back in the same spot(like marked it before starting). And i made the slip joint yoke and center yoke line up but when i put it back on it vibrates very bad now. Has anyone experienced this? It was not unbalanced before. Can anyone help me as to why it is unbalanced now?

Maybe you need to rotate the shaft 180 degrees from where it is mounted on the differential.

Are you saying take the four bolts out of the diff end and rotate the tires so the flang rotates 180 degrees? Or pull the slip yoke out and rotate the whole driveshaft 180 degrees?
I already pulled the slip yoke out and rotated it. Didnt help.
Its a pretty violent vibration so im thinking its something simple but i need ideas. I assembled the thing back in phase...

Are you saying take the four bolts out of the diff end and rotate the tires so the flange rotates 180 degrees.

That would be what I would try first. The other thing that comes to mind is that maybe one of the u-joint caps came off and one of the needle bearings got put back into the end cap wrong, offsetting the centerline of the driveshaft. That happened to me once so I know it's easy to make that mistake.