I am having a similar problem with my rear tailshaft vibrating when i back off at speed.
Sounds like the transfers are rattling badly.
Have been told the uni joint angles are too steep.
Tried to decrease the angle on the shaft [ 15* ] tried rotating the rear diff pinion angle around to see if the vibration goes but it's still there.
The early hilux uni's are a lot smaller than later models, what is your rear uni?
Is the pinion pointing at the transfer?
Mine is going in to get the balance checked, if it's good i will have to go a double cardan joint.
cheers
Matt
