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Mabdaddy
04-26-2005, 10:14 PM
Just threw in an RE 3.5 with SuperRide fixed front lower control arms and adjustable rear lowers. Adjustable trackbar. New steering stabilizer. DT3000's. Had a good alignment. All u-joints are tight. Front driveshaft has two u-joints next to the transfer case. One u-joint next to the front end. Back driveshaft has one u-joint on the front and rear. Back pinion is parallel with the transfer case. Front pinion is not inline with the driveshaft. Down a little. Am getting some pretty good vibes from 30-40mph. New Goodyear RT/S's 265/75R16's. Balanced. I've read conflicting suggestions on pinion angles. Some say it should be down a little in front. Others say inline with driveshaft. Back parallel with the transfer case. Any help would be appreciated!

94 ZJ 5.2 249 new VC

LouisianaZJ
04-26-2005, 11:45 PM
the rear sounds good

the front is going to be a trade off between caster angle (steering) and pinion angle (vibes)

ideally the front should be inline with the d-shaft but that would give you a caster of like 3-4*, you want caster to be around 6*, so your d-shaft has to be a degree or two lower

try decreasing caster angle and see if it helps

ELLLLLIOTTTTT
04-27-2005, 12:47 AM
caster should ideally be between 4-6* for lifted ZJ's.

Mabdaddy
04-27-2005, 08:59 AM
Thanks for the replies!

How about taking the front driveshaft off to see if that's what it is? Can you do this with a 94 249 and not toast it?

What it seems like is that even with adjustable upper front ca's that this isn't the answer. Line the pinion and driveshaft up and no matter what you end up with the wrong caster. Right caster... wrong angle. Sounds like the only way to have the best of both worlds would be adj ball joints?

Mabdaddy
04-27-2005, 09:39 AM
I just checked the printout sheet for the alignment. Says I have 6.87 and 7.11 degrees caster. Camber is -.6 and -.5 which he said he couldn't do anything about without different ball joints. Toe in is .08 and .08.

On the caster, if it's supposed to be close to 6 best case, will me changing it from where it is to 5 or 6 make that much difference? By that I mean possibly a degree or two makes no noticeable difference and you only see something after 4 or 5 degrees? Not knowing how critical it is causes me to ask this.

Sorry for all the questions. I probably try to think through stuff like this too much.

LouisianaZJ
04-27-2005, 10:11 AM
see posts 2 and 3

ELLLLLIOTTTTT
04-27-2005, 11:19 AM
Toe should be between 1/8" and 1/16" toe IN.

Mabdaddy
04-27-2005, 05:08 PM
Going to take it back where I had it lined up and have them change the caster from what it is to around 5.5 to 6. See if it makes a difference. No charge so better to use a laser alignment machine than my eye.

It's interesting how many different opinions you hear though from different people on different sites.

"Pinion angle is the cause of vibration only if it occurs on deceleration."

"Pinion angle is the cause of vibration only if it occurs on acceleration."

"Caster should be set to stock settings no matter the lift." (which is 6.5 - 7.5)

"Caster should be set at 4-6 on a lifted ZJ."

Ah the internet. A cornicopia of information. And everyone is right.

LouisianaZJ
04-27-2005, 05:20 PM
guess you WT MFers still on dialup don't like it when my huge annoying sig takes 4 hrs to load. My deepest apologies.
:finga:

nate
04-28-2005, 10:12 PM
Correct info...

Pull the front shaft, does it still vibrate? Yes? Front shaft is ok... No, well it's the front shaft. Shaft balanced? Yes... well it's either a yoke/u joint that's bad, or your pinion angle.


Going to take it back where I had it lined up and have them change the caster from what it is to around 5.5 to 6. See if it makes a difference. No charge so better to use a laser alignment machine than my eye.

It's interesting how many different opinions you hear though from different people on different sites.

"Pinion angle is the cause of vibration if it occurs on deceleration."

"Pinion angle is the cause of vibration if it occurs on acceleration."

"Caster should be set at 4-6 on a lifted ZJ."

MaineZJ
04-29-2005, 07:26 AM
I know a few people running 4 degrees caster and they are fine


Toe should be between 1/8" and 1/16" toe IN.
that's what .08 degress is close to

Mabdaddy
05-04-2005, 10:59 AM
Correct info...

Pull the front shaft....

From what everyone says, you can't drive a 94 ZJ with a 249 without the front driveshaft as it'll ruin it.

Swamp boy
05-05-2005, 02:53 AM
Then pull the 249 as well... :smt003 :supz:

Mabdaddy
05-05-2005, 06:53 AM
Am looking to do that as my next upgrade. Course only after the engine rebuild (and of course ya gotta tweek it a little when you have it torn down), headers, 3" exhaust, custom double ram air system, new front end with lockouts, and on and on and on. But what fun is having a Jeep if you can't mess with it?

OverkillZJ
05-05-2005, 09:58 AM
Correct info...

Pull the front shaft....

From what everyone says, you can't drive a 94 ZJ with a 249 without the front driveshaft as it'll ruin it.

For testing purposes, if the VC is in good condition, it'll be fine. Otherwise you'll just sit there revving your engine and not moving.