vibrations at 60mph

well first have you changed anything lately?I would work from cheapest to pricey!check u-joints for play,loose bolts,pinion bearing slop! thn check alignment of rearend(drive shaft straight left to right)the thing is drive shafts just dont become unbalanced,unless u changed them or lose a weight which is unlikely! i would geta small pry bar and walk from trani-mount back checking every u-joint and bearings for play! bet ya find it there! let us know!