Weird Vibrations

[Scottm2010]

I have this posted over on LOST, but so far there is no help. So I will try here.

Ok, I replaced both the u-joints in the rear driveshaft today. The vibration/sound is still there. :favorites68:

Here are my symptoms:
-The sound is like a low rumble (like if I was driving on those things on the side of the highway).
-Only happens when I am on the gas at certain speeds.
-I gunned it to see what would happen, and the sound and vibrations got VERY loud! It was in like a pulsing rhythm and sounded like it is coming from my rear passenger side area.
-If I put my Jeep in neutral, then rev the engine to around 1.2 rpm's you can hear the noise.

Thoughts:
-I didn't hear the sound before I put in the two upper rear isolators per side. So I am thinking that this might be the problem.
-My rear is one inch higher than the front.
-I know that you guys said that 3'' of total lift shouldn't be that much of a problem, but is it a problem they are at two different heights?
-Is the rear driveshaft supposed to be at an angle in the first place?

Is my Jeep still safe to drive? I need help figuring out what this problem is! So PLEASE any help is helpful.

P.S.- I am going to try and take out one of the isolators per side tomorrow and see if that helps in anyway. I REALLY hope it does! Cause I have an off-road trip this Saturday, and I have been looking forward to it!

 

[ericautopart]

If you put the jeep in neutral and rev the engine you can hear a noise but no vibrations? What type of noise?

 

[LibertyTC]

What year KJ and OME Lifted? What tires?
What is the front measurement from center of tire hub to bottom of fender flare?

 

[Scottm2010]

Thanks for the quick responses.

The sound is like a deep low rumble. I will put it in neutral and try it again, and let you know more of what happens.

It's a 2003 Liberty Limited. It has a 2'' BDS spring lift, then I have the front strut spacer and then two upper rear isolators per side. The front measurement is 21'' and the rear is 22'' with the stock tires. I had it lifted by a shop and they aligned it afterwards. They installed the front shim plate (or whatever it is called), but not the rear isolators. I did that myself. Which is when I started hearing the low vibration rumble noise. So I replaced the u-joints thinking that would take care of the problem... but it didn't. So now I am thinking about removing one upper isolator per side and hopefully that will make the noise stop. I was thinking that the two isolators that I put in made the rear driveshaft now be at an awkward angle.

What do you guys think?

 

[rockymountain]

Thanks for the quick responses.

The sound is like a deep low rumble. I will put it in neutral and try it again, and let you know more of what happens.

It's a 2003 Liberty Limited. It has a 2'' BDS spring lift, then I have the front strut spacer and then two upper rear isolators per side. The front measurement is 21'' and the rear is 22'' with the stock tires. I had it lifted by a shop and they aligned it afterwards. They installed the front shim plate (or whatever it is called), but not the rear isolators. I did that myself. Which is when I started hearing the low vibration rumble noise. So I replaced the u-joints thinking that would take care of the problem... but it didn't. So now I am thinking about removing one upper isolator per side and hopefully that will make the noise stop. I was thinking that the two isolators that I put in made the rear driveshaft now be at an awkward angle.

What do you guys think?

To be clear: you put in 2 extra and have 3 isos on each side or you put in 1 and are running 2 isos per side?

 

[Scottm2010]

I added two per side. Is that my problem, was there already one there? Meaning that I have 3 now instead of what I thought I had, which was 2?

Wow, I just made that confusing..

I added 2 per side in addition to what ever was there stock.

 

[tjkj2002]

I added two per side. Is that my problem, was there already one there? Meaning that I have 3 now instead of what I thought I had, which was 2?

Wow, I just made that confusing..

I added 2 per side in addition to what ever was there stock.

No the added isolators is not your problem.Sounds like a exhuast vibration your hearing since it can be replicated with the engine in "N" and rev'ed up some.

 

[Scottm2010]

Are there any certain spots that I should check that you know of tjkj?

So you are saying that my isolators are probably not the issue? I was thinking it might be just because I started hearing the noise after I installed them. I'm just trying to get things straight, sorry if it comes off as being rude.

 

[rockymountain]

If it isn't exhaust you could try just 2 isos per side. When I did my lift I got a rumble too. I only added 1 iso for 2 per side. I didn't like how it sat anyway so I took out the extra iso and the rumble went away.

Maybe the vibe you have revving the engine isn't related. You did say rear passenger area tho so make sure the exhaust isn't laying on something now. Maybe the mechanics did something to it. :emotions34:

 

[Scottm2010]

Ok, I will check my exhaust first then I will move on to removing an isolator if the problem is still there. I hope it is just the exhaust, cause I like how mine sits, and I don't really have time to remove them. But the part that worries me is that I wasn't hearing the sound or feeling it before I added the isolators. Hopefully, as much as I hate to admit it... I hope that I screwed something up on my exhaust (nothing too big though, haha). I just don't want it to be a driveshaft issue.

 

[Banditsteve]

No the added isolators is not your problem.Sounds like a exhuast vibration your hearing since it can be replicated with the engine in "N" and rev'ed up some.

I am with TJKJ on this one. I assume you mean when the Jeep is stationery? If it does it when it is stationery it is nothing to do with the suspension or drivetrain etc but caused by something vibrating on something else. If it does it when stationery, get someone else to replicate the noise while you have a look underneath and you will soon find it. Taking all safety precautions into consideration obviously!! Hehe. :smokin:

 

[Scottm2010]

Yeah, I tried it when it was stationary and then gave it some gas and you could hear it. Which is why I questioned the whole driveshaft issue, but then again, I started hearing it AFTER I put the isolators on.

I will do some more "tests" and see if I can get any more information. Hopefully find out what it is.

 

[Scottm2010]

Ok, so I checked it out some more and I definitely think that it has to do something with the exhaust. I had it in park and revved the engine and I could hear the sound.

I looked around the exhaust and I saw that I have a very small little whole in the muffler. Also the "diamond" shaped connection between the catalytic converter (I think that is what the part is called) and the muffler must have a hole in there somewhere because water was dropping from it and when I revved the engine since it was cold out I could see some "air" coming out of it.

So hopefully this is all ok. What do you guys think? Does this sound like it could be the source of the noise and vibration that I am describing? Did I finally find the source?! If you guys think that this is the problem, is it still safe to drive? I would think so. Eventually I will get a new muffler, but not until I get some money.

 

[Banditsteve]

I am with TJKJ on this one. I assume you mean when the Jeep is stationery? If it does it when it is stationery it is nothing to do with the suspension or drivetrain etc but caused by something vibrating on something else. If it does it when stationery, get someone else to replicate the noise while you have a look underneath and you will soon find it. Taking all safety precautions into consideration obviously!! Hehe. :smokin:

Most exhausts have small holes in them, usually at the lowest point to let water out so they don't rot as quick from the inside. A biproduct of burning fuel is a load of water. You normally only see it when the engine and exhaust is cold because as the exhaust gets up to working temperature it evaporates the water. Thats why you sometimes see water coming out of exhausts and you can see it better on cold mornings. Are you sure it is a "vibration" your Jeep has or does it just sound like one? Obviously we can't tell from here but it may be that your exhaust is blowing and sounds like a vibration? Stick a cloth over your hand and cover the exhaust pipe end and if there are any holes in the system it will come out of there. It might be hot so be careful. I always like to state the obvious, it comes with working with idiots!! Hehe. :smokin:

 

[Banditsteve]

Yeah, I tried it when it was stationary and then gave it some gas and you could hear it. Which is why I questioned the whole driveshaft issue, but then again, I started hearing it AFTER I put the isolators on. I will do some more "tests" and see if I can get any more information. Hopefully find out what it is.

Exhaust touching something around the back axle area? Body will be sitting a bit higher from the axle now and might be touching something it wasn't before? Turn engine off and give the exhaust a wiggle and shake and see if you can see or feel it hitting or rubbing on something? Just a thought. Good luck. "Seek and thou shalt find" as somebody famous once said!! :smokin:

 

[Scottm2010]

I guess it just "sounds" like a vibration. However when I am driving on the highway it sounds like it is vibrating AND I think it is actually vibrating because it seems like all hell is breaking loose in the back.

I went out just now and checked the exhaust and I think I might of found the problem area. I am going to upload a picture of it now and see what you think.

 

[Scottm2010]

Ok so here is what I found... what do you think?

You must be registered for see images attach

 

[Banditsteve]

Ok so here is what I found... what do you think?

You must be registered for see images attach

Yes that's probably it Scott. How did it get bent? Did you jack it up there or something? Hehe. You can see where it has "peeled away" from where it was. Piece of wood and a hammer to knock it back to where it should be and that should cure it Matey. If only everything in life was that simple eh? Well done. Good luck. Let us know how you get on. Steve

 

[rockymountain]

hmmmm. how did you put in your isos? did you try to stick a jack between the body and the axle? Anyway, glad you found it. That musta been one hell of a racket. :freak3:

 

[Banditsteve]

hmmmm. how did you put in your isos? did you try to stick a jack between the body and the axle? Anyway, glad you found it. That musta been one hell of a racket. :freak3:

It's known as the exuberance of youth! We have all been there! Long may it continue! Hehe. :smokin: