Hello,

I have a 2000 XJ Freedom edition (I'll give more details below). After I installed a lift, among a number of other things, I have been experiencing a drive line vibration. It sounds like it comes from the rear shaft, but it's hard to pin-point. The vibration starts in very subtly at 65 and seems to worsen. I have double cardan shafts in both front and rear. The front pinion sits at 3-4 degrees BELOW the center-line of the drive shaft (the front shaft is sloping at 12 degrees). The rear pinion sits at 1.5 degrees ABOVE the center-line of the drive shaft, however I've been messing with that one and I need find shims that will return it to 1-2 degrees below that center line (the rear shaft is sloping down at 12.5 degrees).

Critical Info:
-3.5" (closer to 4) OME lift with full HD leaf packs
-Rusty's 1" drop T-case bracket
-7 Degree axle shims
-Double cardan shafts Front and Rear
-Both axles are rebuilt within the last year
-SYE
-Stock upper and lower control arms

If you have experience in this matter, I would greatly appreciate some input. Thanks

 

You have an sye get rid of the tcase drop. Did you measure before you put massive shims in the axle.

 

I can't get rid of my t-case drop as it is my cross-member. I did fab up some 1/4" plates to add 3/4" lift in the transfer case bracket....it made the situation worse, so I removed them.

Believe it or not, I did measure. I put those shims in place as a test set. I will be removing them and re-installing some 3 or 4 degree versions after I re-check angles.

 

Once you fix the axle angle the vibration should go away. I would get a junkyard factory cross member to bring things back up. The spacer probably made the angles worse which is why the vibration got worse.

 

I was talking with someone on NAXJA and he suggested I look into adjustable control arms to fix the front caster angle....so I'll probably order some this week. The rear, I'll clear up with the right shims. The vibs are better now that I dropped my t-case, even with the sye, which is weird.

 

Adjustable arms are really the option in the front. The angles happen to be better with the drop. Remove the drop, measure and get the right shims and the vibes should go away.

 

Remove the drop. End of story. They cause more problems than they fix.

 

seven degrees of shim is way too much as you have discovered. 3 to 4 degrees sounds like too much also. When adjusting the pinion angle for front end, I found that a large turnbuckle from home depot can be used in the place of one upper control arm for adjusting your pinion angle, works great just turn the turnbuckle the direction needed for proper pinion angle and install the other upper control arm, remove the turnbuckle install the other side control arm and check your angles.

 

So I'm curious which cross-member your'e running? Only after market ones I really see are for long arms which it doesn't sound like you have. But like everyone else said get rid of the TC drop and the shims, I have RE 3.5" full springs with a SYE and no shims. absolutely no vibrations