ok, i've decided that the rear is fine after lots of driving like you guys said above. totally livable amount of vibration for me... and like spanky said above th ediff seems to be living fine.
so, i pulled the front ds just now to see if th etransfer case output flange was not wobbly and the nut was tight.. they are both fine... as is the pinion flange in th efront. all tight. anyways.. that basically leaves the front driveshaft. It is pretty solid, no weights have been thrown, and after lots of driving around here in the past week in slushy conditions in and out of 4wd with the front hubs locked i have noticed it only vibrates when th ehubs are locked and it is in 4wd and there is slack in the driveline. with just the hubs locked and the driveshaft freewheeling it never vibrates (not even at 80mph).
So, two questions.
one, does it matter if the slip yoke is near the transfer case or near the diff? it was set up near the diff when i got it, so thats how i put it back.
Two, how much slop in the slip yoke is ok? it has a bit of slop (like wiggles in the direction if you were to try and fold it in half) but i dont know if it is too much. it is less than the rear. I am about to go for a drive and see if it makes the same vibraton in 4wd with the driveshaft removed. hopefully that will certianly rule out the transfer case.
also, the shaft is "in phase" as far as i can tell with it out and looking straight down the flanges.