Bluebyu

So my jeep is now at 5"s of lift. Before this there was no vibes on the front end.

The axle is shimmed properly in the rear and this vibration is not coming from the rear it is in the steering wheel. My tires and wheels are balanced, it did not vibe before when I was at 3"s and it is not my front driveshaft because I have taken it out and the wheel still shakes. What's weird about it is it comes on right around 27 mph and by 33mph its gone.

My track bar is adjusted properly, and all my joints and fittings are good and greased. Could I have thrown my alignment completely out of wacky and is this the cause?

ta2tony

Did you re-align it after increasing lift? If not, I suggest you look up the driveway alignment.

muffinman

Did you get this figured out?

Bluebyu

not yet, im doing my rear shims this week tot get rid of the drear dive line vibe. I'll look into aligning it this week as well..

muffinman

Keep me posted and I will do the same, having same problem except mine is from 30-35 mph.It's weird, 29 mph is fine,36 mph is fine. My rear end is shimmed properly. Took front shaft out and it still has the vibration in the steering wheel. Mine vibrates if I am accelerating or coasting. Put it in neutral at 33ish mph and it vibrates.

Bluebyu

Ive been reading up on it and I think its either caster needs to be adjusted, or I need to re adjust my track bar. and make sire its all tight.

Mine started vibing in the front end like this right after I put in my 2" coil spacer, RC lower control arms, and my 2" extended rear shackle. My alignment still looks good though which is why I didn't go get one yet, I have a feeling even if I did it wouldn't cure my issues.

Let you know what I find when I adjust my trackbar, its like a 1/4" off.

buckshot500

When you have lifted a vehicle to the point of needing caster adjustment, this means the pinion angle will be changed. The pinion needs to point towards the transfer case yolk. Caster adjustments cause the pinion to be pointed further downward. There is a point where it can't be compensated for any more with adjustments. The axle "C's" need to be cut loose, then the pinion angle reset, then the C's need to be re-welded to the axle tubes. I'm not sure if a 5" lift is enough to cause this, but it would certainly be suspect.
These images show what angles are needed.

http://www.google.com/imgres?q=image...2&tx=163&ty=64

http://www.google.com/imgres?q=image...14&tx=95&ty=23

Bluebyu

The thing is though it does it without the front drive shaft in so would it still be this? The pinion angle shouldn't matter if the shaft isn't in no?

muffinman

Yea, pinion angle won't matter with no shaft. I have drove with both shafts out, no not at the same time! Still get the vibration. My rear end is shimmed per the single cardan shaft specs. Parallel.

buckshot500

Agreed. Without the frond driveshaft installed, it would have to be something other than what i was thinking.

cdn_xj

recheck all of the bolts and bushings in the front suspension and steering. I had the same issue. turns out most of my control arm bushings were worn to the point of needing replacement. it's basically a very mild death wobble.

the key is that it occurs within a specific range of speeds .

With respect to front pinion angle and caster:
After lifting the ideal front pinion and caster angles are contrary to each other. given the choice, you are well advised to sacrifice caster angle in favor of pinion angle. Usual rule of thumb is to adjust pinion angle just to the point of eliminating front driveline vibes.

At 5" of lift you should be able to come to a compromise.

this is, of course, easier with adjustable UCAs and LCAs.

Bluebyu

Yeah I think I'm going to pick up a pair of iro adjustable upper control arms