CherokeeJake1

I lifted my 00 xj 6.5 inches short arm. First drive had a death wobble about about 35 mph.. Took out my front drive shaft as a possible solution. Now goes 0-75 with no vibrations. My pinion angle or castor angle? not sure which is which or if they are the same thing just from reading other posts that must be my problem. I have adjustable upper and lower control arms so im assuming i need to shorten lowers to make the angle less? hopefully someone can point me in the right direction here, thanks

Rockfrog

If it was a vibration, it was NOT death wobble, removing a driveshaft won't cure death wobble.
That said ... Pinion angle and caster angle are related, pinion angle is the cause of your vibration. At 6.5" you may have trouble reaching a good angle with the stock low pinion 30.
Lengthen the upper to rotate the pinion up, and shorten to rotate down (the opposite holds true for the lowers). IMO it's better to adjust at the uppers. They are aslo easier to get on/off at the axle as well.
You want the pinion pointing at the tcase output, but with an LP30 that will screw your caster angle. You will have to find a happy median between the two. Or swap in an HP30 and be done with it. The higher pinion lends to better angles at higher lift heights. Not knocking the lp30 but it does have it's limitations at this point.

CherokeeJake1

Yes i mispoke it was much much more than just a vibration. Anyone know the proper length both the uppers and lowers should be to have the correct angle? thanks again

caronaxtr

The directions that came with your lift should have given you a baseline to work off of. I've got a 4.5" lift & 1.75" spacers (up front) and 1.75" shackles out back to get me around 5.5"+/-. I had to keep adjusting till everything was happy. I also did swap in a HP30 recently to help with it.

Basically there isn't an exact length for them. Trial & error will dial it in correctly.

CherokeeJake1

Yes trial and error is what i was thinking i was going to have to do alright thank you for the help!!

wrapstar

You want your caster between 6* and 8* measured at the flat on the bottom of the inner c. With short arms it's gonna be impossible to get everything right.

Rockhead

Hey CherokeeJake1. Some of the information you have received in this thread isn't quite right. Your front differential pinion does not have to point up to the transfer case like the rear does. The front drive shaft has a double cardan u joint so as wrapstar said, just set the proper caster angle and you should be ok. With the upper and lower control arms both being adjustable, setting the proper angle should be easy.

CherokeeJake1

Alright that sounds like the news i was hoping to hear.
Thnks all again for the help

98cherokee531

If the pinion up front is not in line with the driveshaft, the slip joint in the front driveshaft will begin to wear out quickly or if it's already loose, it will hum going down the road. Cv style driveshafts are designed to run the angle in the top two u joints and the pinion u joint is to be close to in line with the rest of the shaft

wrapstar

This will cause wandering and bump steer. I battled this for along time trying to find the happy medium wasted tons of time and u joints before listening to the guys that told me to use the factory specs of 6* to 8*. And they are people that do this for a living.

98cherokee531

Fair enough, if it worked for you then run it. I feel not all xjs react the same to certain specs.

CherokeeJake1

I will have to try both methods and see what my jeep feels like doing. I appreciate the input of everyone thanks again

wrapstar

You're also moving the camber that far out of spec as well causing the tires to wear on the outside. Factory spec is factory spec all Xjs are built within spec

beasticles

Over six inches of lift and you expected your pinion angles to be okay without adjustment? You need Adjustable upper control arms to set your front pinion angle, and adjustable lowers as well assuming you aren't running drop brackets. I run 4" of lift and I needed those things.

kickice24

I can tell you from my experience with an HP30. If you don't get that pinion angle close, you'll not only ruin the slip in the front d/s, you'll also ruin the pinion bearing. I found out the hard way. I, unfortunately, have to put 70 miles on mine a day and that issue rears it's ugly head quickly with highway miles.