vibration and squeak

Hi all hope some one can help i seem to have a vibration and a squeaking noise from under my disco at low speed and accelerating i had the same thing when a uj was worn. The uj was replaced and it stopped but has now come back but all of the ujs are fine the only thing i can find is a small amount of play in the front output flange on the transfer box and a small amount of oil. Would this be the cause of my problem and if so what can be done to sort it out. Any help would be greatfull.

It could be that one of the universal joints has not been kept lubricated properly and has become contaminated with water causing it to rust.
I had a uj that become rusted and it distroyed its self in a very short time.
If the transfer box is full of oil then even worn bearings wont squeak.