Anyone ever forget to mark their driveshaft before removing it and after you reinstall it, you have severe vibrations at ~65mph?

well, that's what i did. =/

I'm thinking that to fix the situation, all i have to do is rotate the driveshaft 90 degrees (4 bolts) and rebolt it up.
if the vibration doesnt stop, i do this until it does stop.

4 positions total (90 deg apart) for the driveshaft to be installed--i think.

OR am i screwed??

what are your thoughts on how to fix this?

Thanks,

mechttu
houston, TX