Lifted my truck, got q's

AT what height do I need an SYE? I just put my lift in and I'm getting vibes at different speeds, BAD vibes almost feels like it's coming from the front end. Also my leaf springs don't have the wrap-clips on them, if I put the clips on them will that bring the rear end up?

Basicaly my lift is 2" springs& 2" spacers, and 2" springs in the rear(sagging a little) and 2" shackles. The front end sits up almost 2-3 inches higher than the rear....

wrap clips? are you talking about the leaf clamps that hold them together? if there are spaces inbetween the leaves then you have a problem. Depending on the year of the jeep and the setup, you may or maynot need a sye at a certain height. i am sure your rear pinion angle is the suck right now because of the shackle. Your gonna have to take some pinion angle measurements, and proably drop the t-case too if you wanna get rid of the vibes until you can get a sye

i know guys that run 6.5 with stock drive shafts and no sye. so i guess up to 6.5 is ok.

swany said:

i know guys that run 6.5 with stock drive shafts and no sye. so i guess up to 6.5 is ok.

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everybody kinda knows some guy that did something that worked but it cannot be applied in all cases, plus at that lift the angle of the joints at the t-case is pretty bad. I have a 3in rear lift on my 96 and tried everything to get rid of the vibes, before i went to a sye. Also when you get a sye you are gonna have to set it up right so you get no vibes from it.

So i dont think 6.5" is the number you should go off of, 1" could be too much in some cases.

i run 6.5 lift on my 99 no vibes no sye however one of the guys i work with has 6.5 and has to have sye due to bad vibes bith had t case drop his is a 94 dont really think this will help you but i just felt like saying it

Zoro said:

AT what height do I need an SYE? I just put my lift in and I'm getting vibes at different speeds, BAD vibes almost feels like it's coming from the front end. Also my leaf springs don't have the wrap-clips on them, if I put the clips on them will that bring the rear end up?

Basicaly my lift is 2" springs& 2" spacers, and 2" springs in the rear(sagging a little) and 2" shackles. The front end sits up almost 2-3 inches higher than the rear....

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*Sounds like you are at 4"...have a spring shop setup or rearc your spring to level it (or build a better bastard pack)
*Start with a Transfer case drop, you don't say what year yours is, but the 96+ is prone to vibes at 2-3 inches and higher. If you are too high the driveshaft will fall out if you don't use a SYE and a longer shaft
*I made a TC drop of 1 5/8" using Uni-strut (Super strut)...some people use 1x2 inch tubing (harder to find).
*pic (with a warn skid plate) of trail rig:
http://www.lp2aenergy.com/PDF/97XJ/P9040034(Small).JPG
*If your Jeep is an 00-01 it might have a low pinion Dana 30, ...which means you have to change the pinion angle for the DS alignment

*If your Jeep is an 00-01 it might have a low pinion Dana 30, ...which means you have to change the pinion angle for the DS alignment

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Question. How do you change the pinion angle on the front axle?

Sorry about the year part, it's a 1990...I took it to get an alignment yesterday because I replaced the tie-rod& drag link and it still pulls a little to the right, I put bigger tires on and lined the driver side tire up w/the fender and the passenger side tire sticks WAY off center...I didn't put in my adj. trac-bar yet but should it really have that much of an effect of the alignment? All the specs afterwards on the printout were in the green.

I'll try to get some pics up over the weekend so ya'll have an idea of my dilema here.

Littlewhitexj said:

Question. How do you change the pinion angle on the front axle?

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Is this a rhetorical question? You are right, you can't change it per se...it is part of the caster angle. You can however replace the low pinion axle with the high pinion axle from a salvage source.

cha ching.

Like mentioned above a high pinion axle(what you have in your 1990 xj) is better than a low as far as pinion angle is concerned,
but............

You can change the front pinion angle using one of two different approaches
1.Install adjustable arms
2.Use stock alignment shims(limited to how many shims you can fit)
All of which affect your caster

Caster by nature on a 4x4 is supposed to be secondary to pinion angle,at best it's a compromise(but doesn't have to be).The approach I plan to take is to install adjustable control arms to get the best pinion angle possible and then have my knuckles cut and turned or use adjustable ball joints to get the best caster.This way I don't have to compromise bettween having good pinion angle and "ok" caster.....it's the best of both worlds,imo.This is my situation with a 5.5" lift and a high pinion axle your experience will vary depending on what size lift/axle you have.All the above info is based on the assumption that the rig will be driven on the street,if it's a trail only rig caster is not that big of an issue.... pinion is always an issue whether its offroad only rig or a dd if you ever plan to use 4wheel drive,which I think we all can agree that we do and will.