Need some Help With Driveline Vibs

[GTABurnout]

Ok quick back story.

2000 XJ NP231 OldMan EMU 3" lift. 4 degree shims on the rear leafs.

I am having a hell of a time with this. First befor the shims I had horrible driveline grinding and vibe on both accel and decel. The decel would only happen on ocasion but it souned like the jeep was going to gring to a hult.

After the 4 degree shims I was having no problems un till today on the wway to work. It feels like a dead u joint but it makes more noise under decel and braking then under accel. I plan to pull the drive shaft and chet it out tonight. Should I plan on just having to put u-joints in? Does it sound like sometheing else? I have heard of the accel vibs being u joints but never heavy decel vibs. Any help would be great. I am just pissed off at the dam thing now so I want to be able to at least drive the dam thing to work.

Thanks
Hunter

[John in AZ]

If no problems before today I would think that the ujoints would be a good guess. As I read it the shimms fixed the problem then all is fine then starts new problem. So unless something came loose it has to be a failure of something & they seem most likely.
John

[garr]

3" lift on a 2000?
I see a slip yoke eliminator & CV driveshaft in your future!

[GTABurnout]

SYE is nexts months buy, untill then I want to drive it and work out some other bugs but I am loosing confidance in this thing with all the little problems I have been having with the drive line.

I will do u joints tonight hopefully and go from there.

[garr]

SYE is nexts months buy, untill then I want to drive it and work out some other bugs but I am loosing confidance in this thing with all the little problems I have been having with the drive line.

I will do u joints tonight hopefully and go from there.

Don't bother with the U joints, Your vibrations will only be cured by a SYE, CV shaft & rear shims.

When you lift late model XJs even 2" You will almost always get rear driveline vibes because of the long unsupported Transfer case output shaft, I had bad vibes at 1.5" of lift on my 01 !

[James98XJ]

I have about 2.5" in the back and the 242 and 8.25 and no vibes.

[garr]

I have about 2.5" in the back and the 242 and 8.25 and no vibes.

What year?
+ remember the op does have vibes, He needs them cured!

[John in AZ]

Well garr I would agree but in reading the whole post he said after the degree shims all was good for a while & they came back suddenly seems like has to be something wore out.
John

[garr]

Well garr I would agree but in reading the whole post he said after the degree shims all was good for a while & they came back suddenly seems like has to be something wore out.
John

Correct, Without a SYE & CV shaft at those angles he is going to keep wearing out U joints FAST!!
On a 2000Xj the output shaft of the TC is just hanging out too far unsupported, I would be suprised that @ 3" of lift he has not developed a leak around the output seal, I have seen lifted Late model Xj TCs that had to be rebuilt because of all that flexing.

[A7XJ]

I have a 2001 with a 4.5 lift and am getting by with a t-case drop and shims in the rear. only have vibes when i leave a light. If i feather the throttle then i don't get anything. sye coming soon i hope.

[AZXJ]

Check the cardian on the front Driveshaft. Make sure your U-bolts, and centering pins are in tight.. Also Chec to make sure your U joint straps are tight, and your Yoke is tight. I'd also consider bumping up to 6 degree shims .. Once the SYE is in you'll be set..

Dave

[stewie]

I would start by crawling under the rig and checking things out. Hell, its free and you may spot something (related or otherwise) where if you find it now its no big deal, but let it go and it gets wor$e. Check the U Joints in both the front and rear drive shafts. Even if they "apear" to be good, they may not be. In my old rear driveshaft the u joint was bad but still tight. when i tried to see if there was play within the DS, there was none. But after removing the DS, I rotated one of the caps and it was not smooth at all. Also, check the CV on the front DS as well. If any ujoints or cv's are greasable on your rig, be sure to grease them yourself or actually watch the idiots at the oil change shop do it- I learned from experience they often dont.

Check both DS for damage. i had drug the front DS (that had become my rear one after SYE) over some rocks on the trail. it ripped off the grease zerk and balanceing weight. I got vibes from that. now, its gonna be my trail spare after I get off my butt and do it.

You may want to remove your front DS just to eliminate the front end. If you remove the front ds, and the problem is still there then the front end is not the culprit. If it does, then something is wrong in the front end- be it DS, axle u joints, tire/wheel out of ballance, alignment etc.

It may be a little daunting and flustrating trying to figure the source of vibes, but if your thurough and systematic it can be done.

[GTABurnout]

Ok well I changed the bad U joint in the rear and it got a little better. My bet is the other u joint is also bad. But I get the bad vibs when fethering the throttle or when lightly tapping the throttle, on and off.

I think I will just order a SYE next week and hit up a junk yard for a new front shaft to have rebuilt.

[jeep pox]

Mwahahaha I'm on 6.5" lift with a TC 1" drop no vibes. you can check my driveshafts they do not touch. no shims. But i suppose its cause its Jeep Pox and well you just don't get much better then Jeep Pox :D But then again what does a vibe feel like. . . . i run 35" MTR's before that they were TSL's. . . . hmmm you tell me if something new is vibrating :D

[GTABurnout]

Well u joints only sort of helped. I will be ordering a SYE this weekend. I am a little pissed. This cherokee has been nothing but problems. It may go up for sale after the SYE if it still doen't feel right.

All I want this thing to do is cruise on the freeway at 75 with out trying to kill me, is that too much to ask?