RE 4.5 installed, now muliti vibs HELP!

all right, 93 cherokee automatic. RE 4.5 (leaf springs), t-case drop. 32's preformed alignment after lift was installed.

now i've test drove this and have ALOT of vibirtions, the one that scares me is the on that

1) if i step on the brakes from faster speeds to a hard stop it sounds like the brake rotors went metal to metal with the pad
2) i'll be on a steady speed 35-40 and all of a sudden it sounds like a tire rubbing on a mud flap.
3) decel, same mud flap sound. for about 2-3 seconds
4) i think this is a t-case drop problem, i can feel the motor vibrating harder in drive and sitting at a stop light.
5) constand small vib most all the time. i know the tires (MT/Rs) will give me some but i think it could be something else.

do i need a SYE kit to cure all these problems? or do i have different problems like 2-3 issues.

~Zack

Sorta sounds like the transmission mount is causing some of the noise/vibs...check that and the exhaust over the crossmember...might not be all the problems but sounds like some of it.

how many miles are on it? Reason being because I put a lift on a cherokee that had high miles, and all it needed was u-joints. that had worn little grooves in the cross from the rollers. when it was lifted the u-joint had to work over a wider range and it cause the rollers to move over the grooves causing a vibration

about 112,000

pull the cap off the u-joint, and just check the cross and make sure they are smooth before you go spending money, and more time. I'm not saying you may not have other problems, but check the easy things first.

Justin

one other thing, you said you put a leaf pack in....did you put the degree shims in...or facing the right direction?

I suspect there are several issues:
1. I would make sure the rear driveshaft is at the right angle (search) you probably need to shim the rear axle to get it right.
2. I would replace the U-joint in the rear driveshaft at a minimum. Personally I would replace all of them (they should be done anyway if you have not recently).
3. Check to make sure nothing is rubbing (exhaust, transmission, mounts, leafs, brake lines, etc).
4. Make sure that at full droop everything is ok (brake lines, driveshaft, shocks, etc).

Start with these and see where it get's you.

Michael

no i haven't put in degree shims, yes i know that that larger part of the shim goes in the back. is this going to make that much of a difference? i'm sure that the U joints are good. i don't know about the braking part. i've put all new brakes on this jeep before i put the lift on. i drove it on some half melted snow that had rocks and junk in it. i don't think i got rocks in my rear brakes with the short time i've drove it over the snow. yeah alaska.

~Zack

the shims will take care of alot of the vibes...

SYE or a tcase drop until you can get an SYE.

You might have(more than likely) have one or both of your motor mounts worn out. This can lead to drivetrain vibrations galore!

The sound you describe as the tire/mudflap sound reminds me alot of when I lifted the ThumperXJ same year as yours, and found that the ujoint coming out of the transfer case on the rear driveshaft was binding horribly. My fix was a Rubicon Express slip yoke that my brother had from another XJ that got wrecked. Solved my issue. HOWEVER, ThumperXJ has only 4 inches straight of lift. OME, Spacers, and shackles. You would benefit from having an SYE, and it would possibly negate having to have the tcase drop. Do check yer motor and tranny mounts its NOT fun when one gives out completely, and especially not when yer slinging through some mud at relatively high wheelspeeds or crawling over some trail somewhere.

all right, i've solved the braking problem, it was the new rim, steel U.S. wheels. has the chorme center cap not causing the rim to correctly seat on the hub.

i'm probaly going to the CV rear drive shaft. in a few weeks, i don't need to drive this right away, plus i'll need some transmission work at the same time i'll be installing the SYE kit on the t-case. then remove the t-case drop

this other noise starts at 55MPH and sounds like a high pitch bearing buzz. comming out of the t-case. a SYE kit will fix this?

~Zack