Bad Vibration!!! Not Death Wobble! need help! have searched!

[BlueCuda]

I bet the slip is worn in the front shaft. Thats what caused mine.

 

[RockyCodeHead]

I so could have written your original question myself!

Your description of what your rig is doing is exactly what mine is doing.

I too have had DW and resolved it and this problem I am having is definitely not the same. It could be a tire that goes out of round I supposed. Perhaps I should put 32psi in my tires. I usually run them around 20-25 because they bulge otherwise and wear in the middle. The truck just isn't heavy enough for full pressure.

I have another condition on my rig though. If I am on a slight uphill, like 1% grade (parking lot type of situation), facing uphill, I put the auto tranny in reverse and start gradually rolling, then tap my brakes, I hear a noticable clunk. I release and re-apply the brakes and the clunk repeats itself. I have redone my brakes and everything is good, so it's not the actual brakes.

I can't do the brakes and look under the rig at the same time so I don't know for sure what's going on, but I suspect a control arm bushing has failed. I am replacing all four uppers tonight. The lowers are part of the new arms I installed with the lift three years ago so I am going to tinker with the uppers first presuming the lowers are statistically OK. (The uppers are original mfg'd 8/86)

Hope you find the cause of your wobble/shimmy/bad vibe soon!

Rob

 

[JJacobs]

Rob, you should be able to see your noise so to speak with a helper. Just have to make sure not to run him over! Usually if you fiddle around with a clunk like that for a few minutes you can duplicate it on flat ground with a little gas and brake, just have to find the precise amounts of each to get it to show up. Once you can make the noise happen with very limited vehicle movement have a helper watch for excessive movement in the upper and lower arms. Also look closely for witness marks to see if the bolts have been moving in their holes.

Sounds like you're on the right track already, did I mention if you have a helper underneath to be careful?

edit: to be nitpicky, you also mentioned you're having the same problem as the original poster. If tires change it, you're not. Tire vibrations and driveline vibrations are very different animals. A tire vibration is much lower frequency, typically about 15 hertz while most driveline vibrations are around 100 hz iirc. Which is why tires are felt as a thump and drivelines put off a buzz.

 

[MarioWario]

Okay so i was driving up to a welding class this week and noticed at about 45 to 50 mph there is a really bad vibration that seems to be coming from the front end. I have rotated the tires and replaced both motor mounts and tranny mount today because all were shot and took it on the highway again and it still happens. Any help as to what this might be??

I recently engaged the front axle full time and got rid of the vacuum actuated 4x4 as advised on here, Could it have anything to do with that?

Its a 1988 XJ 4.0 Automatic with a 4.5 in lift and 33 inch muds. has an AA SYE and np231 tcase.

Im pretty sure it has nothing to do with the drive shafts because when at that speed i threw it into neutral and let off the gas and it did not go away so ive narrowed it down to either the tires or front axle. unless im forgetting something?

Any help would be greatly appreciated!!!

Sean.

this is what ive learned from expierence.
XXXX your jeep, get a little honda for a daily driver and make your XJ a trailer rig.

 

[Vince]

I have a friend on that had airsoft pellets in his Creepy Crawlers. He had a bad vibration at the same speed. Rotating tyres didn't fix it either. He was convinced that the airsoft pellets were not the problem.

We put a set of wheels and tires on it from a TJ that was running smoothly to test it and it did not vibrate at any speed. We broke the beads and vacuumed out the pellets from each tire. The Creepy Crawlers were rebalanced using conventional weights and there were no more vibrations.

A few years ago I had a similar problem with Dynabeads. They were OK for a while, but oily, moist compressor air made them stick to the insides of the tires. I run conventional weights now as I could not guarantee airing up always on CO2.

 

[YEAGS]

I like how everybody immediately goes into death wobble repair mode. He says right in the thread title it's not DW for cripes sake.

Would you characterize the vibration as more of a rapid thump thump, like a tire, or a buzz? By buzz, I mean vibrate the change in the cupholder rhythmically, make the mirrors out of focus?

These are very different vibrations with very different causes. And as mentioned before, putting the transmission in neutral (or even the transfer case) doesn't magically disconnect the spinning driveshafts from the axles.

From what little info is here I'm thinking front driveshaft, but there's no need to remove it. A bad driveshaft vibration can usually be found with a good under-Jeep inspection. Park on flat ground with the trans in neutral, parking brake on and tires chocked. Check each driveshaft at each ujoint, slipjoint, and double cardan assembly (in the front, and also rear with an SYE). Push, pull, twist, and look for play.

Ok so i followed your directions and pushed pulled twisted and turned and couldnt find any play at all really. So I removed the shaft and took it for a spin but the vibration/annoying buzz remained. So then I unengaged my front axle which was fully engaged to bypass the 4x4 vacuum system, took it for another spin and still vibration remained.

What else could be causing this??

 

[YEAGS]

well I discovered the problem. Shot u-joint in the rear shaft. Shaft is tom woods cv about a year and a half old bought when i put in the sye. So im off to pick up a new u joint from napa. will let you know how it all works out. thanks again for the input!

 

[Mutant_Xj]

I just installed adjustable LCA's tonight and that fixed mine. I had a 2 hour drive and was trying to get it to make the vibes and could not.

 

[Fastdemise]

I had some pretty good shakes right at 45-50 to where if I wasn't speeding up or slowing down the steering wheel would shake about a inch either way. The only thing I noticed that was not right was my trackbar mount on the axle was a bit out of round. Drilled it out for a 1/2" bolt and now I only get the shakes over 60 which might just be my anti-freeze balancing.

 

[dogsled1]

I have it with two different sets of tires one set is 31" mud country with airsoft pellets, and the other are stock tires professionally balanced. No matter what tire you put where it's the exact same shimmy.

same here, '01 stock up country package, starts at 55, ends at 60. I'm thinking front axle ujoints since everything else looks OK. Plan to drop the front shaft, then replace the axle joints it not the DS.

 

[dogsled1]

found my issue today, PS front axle has some slop in the joint, everything else looks fine.

 

[x2elite]

I so could have written your original question myself!

Your description of what your rig is doing is exactly what mine is doing.

I too have had DW and resolved it and this problem I am having is definitely not the same. It could be a tire that goes out of round I supposed. Perhaps I should put 32psi in my tires. I usually run them around 20-25 because they bulge otherwise and wear in the middle. The truck just isn't heavy enough for full pressure.

I have another condition on my rig though. If I am on a slight uphill, like 1% grade (parking lot type of situation), facing uphill, I put the auto tranny in reverse and start gradually rolling, then tap my brakes, I hear a noticable clunk. I release and re-apply the brakes and the clunk repeats itself. I have redone my brakes and everything is good, so it's not the actual brakes.

I can't do the brakes and look under the rig at the same time so I don't know for sure what's going on, but I suspect a control arm bushing has failed. I am replacing all four uppers tonight. The lowers are part of the new arms I installed with the lift three years ago so I am going to tinker with the uppers first presuming the lowers are statistically OK. (The uppers are original mfg'd 8/86)

Hope you find the cause of your wobble/shimmy/bad vibe soon!

Rob

Your clunk in reverse is most likely your axle end upper control arm bushings. Mine was doing this exact thing. Have someone else back your jeep up and brake periodically while you stand in front and watch the front axle. I bet the axle is rolling from front to back just a little when they brake, and the clunk you hear is when it stops. If thats the case, change your upper control arm bushings. Could be either end, but most likely its the axle end.