Ok, so here's my story.

I installed a RE 3.5" lift a few months ago in my 98 XJ because the old suspension was shot. After the install of course, I had bad vibrations due to driveline angles.

I installed an AA SYE, and used a front driveshaft out of the JY. Still had vibes, and my pinion angle was definitely off. More research, and I added 4* shims, which seemed to take care of my problem.

I decided to upgrade to a beefier driveshaft, a custom made Tattons. Very nice looking shaft, definitely stronger than the stock front shaft. Put it on and it was very noisy. Pulled it back off and could feel a catch in the double carden joint. Tried to adjust the u-joints but couldn't get rid of the vibes/noise. So I called up Tattons and sent it back to them. Got it back and the DC joint is very smooth, but naturally tighter than the worn front shaft I was using. I assumed I was golden.

Put the shaft back on and the vibes/noise are still there. I confess to being a bit at a loss since the stock front shaft works fine. The DC joint is defnitely larger/beefier than the stock shaft DC, but I wouldn't think it would throw my angles off that much.

So my last resort before I pull this nice shaft off is to see if the experts can find the problem.

Thoughts?

When you unwrapped the drive shaft, is it possible that the two parts came apart and you didn't line up the dimples when putting them back together? Other than that, your angles look good.

I'm new to this also, wondering if you installed shims? I just pickup a 99' with a new zone 3" lift and get vibration at 30mph and 65mph, seller supplied 6 degree shims, and have yet to install, wondering if that would solve your issue? Good luck

Have you tried moving the new driveshaft to the front?

I started with 4* shims for my RE 4.5 lift but had to go to 6* to get rid of vibes. I see you're only on the 3.5 but it might be worth considering.

Nothing came apart when I unboxed it. The u-joint caps were taped and I was very careful not to let them drop at all when I untaped them.

I have been thinking about unbolting it and rotating it 180 degrees. I can't imagine why that would make a difference, but I've seen stranger things.

Shmoo, yes, I installed 4* shims before I put the new driveshaft on. Without them, even the stock driveshaft made a heck of a racket.

Since your drive line is ok with the old shaft but not with the new shaft, I'd say your new shaft has a problem. At what speed do the issues start at?
Pic of my newish shafts.

[QUOTE=Rockhead;3030028]Since your drive line is ok with the old shaft but not with the new shaft, I'd say your new shaft has a problem. At what speed do the issues start at?
Pic of my newish shafts.[QUOTE]

I agree that it is probably the new shaft unfortunately. I suppose the balance could be off. Any way to test that?

I will try putting it on the front and see if the vibes continue. That would definitely point to the shaft as the problem.

Very nice looking shafts by the way!

why does that shaft look so dry. did you grease it? looks like heat discoloration above the splines but below the welds. and what style u joints. solid or serviceable

It has plenty of grease in it, both the shaft and the u-joints, which are serviceable and appear to be Spicers.

On Sunday I took it off to attempt to put it on the front. It was too long by about 1/2" to install on the front. So I checked everything again and reinstalled it. For some reason it is much quieter now, with only slight vibrations all the way up to 75 mph. I don't know what the difference is/was, unless something wasn't quite seated 100% or something, because other than moving the DC joint around checking for smoothness I didn't really do anything to it.

I guess I will drive it for a bit and see what happens. I'm still wondering if it is slightly out of balance or something.

I also had vibration issues with two of Tattons driveshafts. They are heavy duty, twice the weight of stock shafts, which concerns me due to the speed they turn.
Noticable was tight joints that I could not free-up like usual, so I took it apart and found a flattened piece of metal inside top of cap. I have never seen this, maybe it 'centers' the shaft. I removed it and the the joint fit and felt normal.
Vibes persisted, I ditched them and reinstalled stock front shafts on both ends and all was well. That was 2 years ago.

Some u-joints like Spicer Life Series have a flat round plastic piece that goes between the end of the cross and the bottom of the cap. What you saw may have been the same principle.