Doublecardan driveshaft vibrating

I have been chasing vibrations in the rear driveshaft since I put in the RE liftkit. The rear is at 6". In desperation I just took the front DS out and put in in the back and now have zero vibrations. Before I had definate vibrations at about 50mph and a herendous harmonic droning noise at 75mph.

Now I know the obvious answer is that the rear DS is either out of round, not balanced or bent. It has done this from new so it is not bent. I have taken it back and had it rebalanced once so I would hope that it is not a balance or runout problem. So what is the problem. I am going to take it back to the shop who made it (Hardie Spicer Brisbane Australia) next week. I dont know what I am going to do if they say there is nothing wrong with it. I have noticed that it is quiet a bit heavier than the front one.

You could have the bearings in one of the caps dragging. Either from damage or dry lube or tightness. Just a thought.

The uni at the diff end is a bit tighter than think it should be but could this cause vibration.

If the shaft has had a problem since it was new.....and now the problem is solved by swapping shafts...then there is a problem with the shaft...OR...there is a problem in the front axle that removing the shaft removed the symptom. My bet is the shaft isn't straight or they used an implement grade slip. If the shaft isn't straight, especially how the yokes are welded in, it will whack the u-joints out of angle a bit.....or if the indexing is off just a bit.....you can get some wierd droning harmonics like that...been there, have the t-shirt.

If you can't fix it...get a set of Boggers and you will never notice it again.:cheers:

xjdavid1 said:

The uni at the diff end is a bit tighter than think it should be but could this cause vibration.

Click to expand...

Yes, any tightness in the u-joint means it's probably bad.