driveshaft vibration

[ej4x4]

i installed a 2 inch lift,replaced the u joints in the rear axle,including the ball in double carden,still vibrates bad at 15mph. and some at 45 on up.what else can i do,what might it be? could it be the ring and pinnion gears? thanks,i also tried rotating rear half 180 deg. this is on a 94 bronco fullsize.the driveshaft is short and has a slip joint,2 parts, it never vibrated untill i raised the rear. i took out original blocks and installed 2 inch.supposed to be correct for pinion angle.if the drivesahft is bent it should vibrate all the time?

 

[bronc76]

did you check to see if shaft is bent?