shackles and shims

hi, ive posted on here about this before, and have searched for answers, but i just cant seem to get answered. i have heard that without a sye, axle shims will throw the driveline out of wack because of different angles, is this true?

also, i wanted to inch up a bit with some shackles, you only need two on a '94 am i correct, you dont need two on each side do you?

any information would be helpful seing as i am ordering 1 pair of shackles, 3* shims, and poly spacers soon,

ps. i am at around 4.5 as it is

thanks guys

First I would get a SYE. Then think about going higher.

i have no vibes at all now, i guess im already expecting some after the lift, but shouldnt the shims fix that a bit? or is it more of the upper connection that makes the vibrations more evident.

rocklandxjer said:

or is it more of the upper connection that makes the vibrations more evident.

Click to expand...

There really is no simple answer here. If you want to go higher you will need a SYE and shaft. Without it, your stock shaft will have so much angle at the t-case it will be difficult, if not imposible to prevent vibes. Plus your stock shaft will probably be to short and you risk pulling the slip yoke off the output shaft or worse yet, stripping ou the splines under heavy torque.

There is no way anyone here can tell you what * shim you need without seeing the rig first hand.

one shackle per spring.

why do you need more than 4.5"?
'

Aaron

the area where i ride there are a lot of dips and ruts and i am just ripping my flares to shreds, so the extra 1.5 should help ease that a little, as for the shafts, couldnt i just have one of the guys i no extend it an inch or so, wouldnt that reduce the risk of pulling the slip yoke? also, what is the opinion on double cardans, much cheaper and seem as though they do the same thing

You can run a shaft with single u-joints at each end at 5-6" of lift. The u-joint angles at each end will be beyond what's considered acceptable. You'll probably have the front joint binding at some point of axle movement--could swap in a YJ front slip-joint to help with the binding. If you set the angles of each joint equal to the other;IE: pinion shaft angle equal to transfer case out put shaft angle, you may not have noticeable vibration. But don't expect the u-joints to last at these extreme angles. The way you adjust these angles now, if your thinking of going to a double Cardin joint in the future is with shims. Don't think 3* will do it for you. When you do the double Cardin, along with the SYE, you should cut the spring pads loose (replace) and rotate the rear diff up until the angle between the pinion and drive shaft are 0*, or may down by 1 or 2*--to accommodate spring wrap under acceleration.

so do you think extending the shaft would be sufficient (notice i did NOT say good) so i would not have to worry about anything breaking under normal stress and moderate offroading, until i can get the sye?

If you set the angles correct, correct u-joints for ANY bind at full droop, have the correct length drive shaft, drive and "wheel" moderately, it should be OK. I won't go into the circumstances, but I lived with the very same set up just discussed while on an extended camping vacation--drove completely arround the US and across Canada--some mild "wheeling" included, without mishap. I was at 5 inches of lift then, running 33's. Good luck.

thanks alot, sounds like its not going to be too bad till i get the sye, does any one suggest adding an inch to the drive shaft towards the middle, or any other suggestions

Whoops, tried to reply to the wrong post,

I ran at 6" of lift w/o SYE for a couple years. Had 6" full leaf pack, the tcase dropped an inch, 1.5" lift shackles, and 6 degree shims. No vibes. Wheeled it pretty hard with no driveline issues.

Mine has the AW4, so I picked up a junkyard driveline out of an xj with the AX-15. It was one inch longer.

thanks alot guys