Why not break them down, save the internal hard parts and dump the cases? You should be able to get each of them (or the best 1 or 2 ) into smaller boxes. I would bag the parts so they don't rust...
AL
My guess would also be a u joint. If it doesn't get worse when turning look at the front drivshaft. Also check and make sure there isn't snow/iced packed in somewhere causing the noise.