Bad vibration that goes when in diff lock.

Ive been trying to pinpoint my vibration at 1500rpm.

So far ive done all the wheel bearings,rebuilt the swivels,new rear prop rubber,front prop uj's,rear uj's are fine,checked the phase of the front prop.

With the front prop off the vibration goes,with the front prop on and diff lock engaged the vibration goes.

Anybody had this before? If so how do you fix it?

Cheers

Shameless bump.

I have just recently had the same problem. The whole back end of the car vibrated. I took a look at the rear prop shaft and noticed the rubber donut was badly perished. After changing this, much to my horror, I still had the problem. My next task was to inspect the front shaft and I found that if I put my full weight into it by shaking it side to side with my hands, I could feel just a small amount of play in it. I set about removing it and when I got it off The UJ on one end was perfect and floppy so's to speak, but the back UJ that goes into the transfer box was floppy to move up and down, but really difficult to move left to right. I took the plunge and got a new shaft from Paddocks and hey presto, problem solved. The car had been perfectly alright on my drive into work, but the vibration started on my way home very suddenly!