having a bad vibration from rearend between 40-50mph and at highway speeds. i thought center hanger bearing so i swapped out, marked shafts before i removed so they went back together the same way. still have vibration. have already ruled out tires. what else could be the problem? its drivin me up the wall. is it possible that it is a balance issue of driveshaft?

Did you bend the shaft or maybe lose a counterweight?

didnt bend or warp it any, taking to get rebalanced today though. will reply back with update.

I've had u-joints go bad and had a hard time telling they were bad. Would throw the shaft out of balance and give a bad vibration.