while you have it jacked up have someone get it up to a speed where its vibrating and see if you can look under and see whats oscillating. Don't actually get under the car while its running though, very unsafe to do that.

 

You could have dropped a bearing on install of the U-joint. Are you sure this didn't happen?

Have you had it aligned sense you messed with it because if not you could be dog tailing and that could cause unknown issues? In fact what I would do is find a forward section on the frame that is the same on both sides and measure to the center lug on the spring (the one that holds the pack together) and see if they are they same, if not you can move them slightly by taking off the weight and "hanging" the axle with no tire on it and using a hold down strap to pull on the axle either backward or forward whilst you tighten it back down to specs. Then double check the measurement.

 

I had alignment done just after new tires which is how I found that driver side spring was bent near front spring bushing. Which makes sense I've been trying to fix wandering problem for 2 years now. I've measured from front leaf spring bolt to center of axel on both sides at 24". Literally the car was fine prior to leaf spring job. I'm running out of ideas!

 

Are they the same from the front eyelet to the center bolt that holds them together? Because if not that would push your wheels further back and could put your drive line on a different angle so it's wobbling.

 

They are 24" on both sides from eyelet . I think previously they it wasn't that case, because of bent leaf spring behind front eyelet. Was thinking axel yoke, but spun yoke while off doing u joints, and it spins smooth, with no slop. I did replaced Wheel cylinders and wondering if something didn't seat right.

 

The springs may have measured out the same but there were significant changes made to the frame between '99 and '01, mostly in the front though. But, if shape of the spring was changed slightly to account for a pinion angle change it can cause a vibration in the drive-shaft. I would take it somewhere that has a clinometer to check the pinion angle and compare it to the trans output. Subtracting one angle from the other should be near zero.

 

I think you are right . I felt like the the axel had to pivot forward to seat flat on spring, which would change the angel fir driveline. I'm going to replace with spring from 98 Durango, will let everyone know the results, thanks for everybodies help!!