Weird Vibrations

Scottm2010 · **Posted:** Thu Feb 17, 2011 11:32 am

Ok, so here is my problem. I just recently got a 2 inch spring lift installed. Just yesterday I installed 2 upper rear isolators on both sides. Now I have weird vibrations when I am driving. It sounds like a low rumble, almost like there is a car next to me that has their bass on. My question is... Is this vibration coming because the rear driftshaft is now at an awkward angle due to the rear isolators that I installed? It was not making the noise (that I am aware of) before. If it is the driveshaft angle, how bad is that? Does it need to be changed right away? Am I able to just reduce the rear to only 1 upper isolator per side, would that make the sound and vibrations go away? Thanks for your guys' help!

GeoJeeper · **Posted:** Thu Feb 17, 2011 1:35 pm

My first question is, is there a car next to you with it bass on? Secondly, did you get an alignment? How's the handling since the lift? I don't think you should have any drive shaft issues with that level of lift.

Zack A · **Posted:** Thu Feb 17, 2011 2:54 pm

Check and replace (if need) the rear U-Joints. They don't cost much.

Scottm2010 · **Posted:** Thu Feb 17, 2011 3:14 pm

Haha, no there was no car next to me with it's base on. Yeah they aligned it when the after the lift was put on. But it has not been aligned since I added the isolators (hopefully I wont have to get it aligned again, I don't think that I would need to though).

Would buying a new rear u-joint fix the problem if that is what is making the noise? I would think that if I replaced it, the driveshaft would still be at an angle. I will post a picture of it tonight and see if that helps at all.

Thank you for your guys' responses. I want to try and get this fixed as soon as I possibly can.

Zack A · **Posted:** Thu Feb 17, 2011 4:56 pm

If you have bad u-joints it will not allow the drive shaft to move correctly which will cause the vibration. When I lifted mine a few hundred miles later mine went out. Had a vibration at certain speeds then all the time. Replaced them, cost about $20 to do all both. If you do one go ahead and go both.

No problems since.

Scottm2010 · **Posted:** Thu Feb 17, 2011 5:38 pm

Ok, thanks a lot Zach A! You have been such a big help. Just a couple questions.

1.) Where can I go to get new u-joints that will fit? Is there a specific one that I should look for?

2.) When you say that there are two, are they the same type of u-joint?

3.) How hard is it to replace them? Is it as easy as just pulling the driveshaft out and putting the new ones in, then putting the driveshaft back? Does anything else have to be changed or bought? Are there any special tools needed?

Sorry for all the questions, I'm just trying to make sure that I get it all right and that I'm not taking on too much.

Zack A · **Posted:** Thu Feb 17, 2011 6:22 pm

Just got to your choice of auto parts store and they can get what you need. If I remember correctly they are the same size, but don't quote me on that. It depends on how rusted in they are. Mine..well...luckily I did mine while I was on duty at the firehouse, it took a blow torch to get them out. After that it was easy.

Do a search, their might be a how-to somewhere.

Scottm2010 · **Posted:** Fri Feb 18, 2011 12:56 am

I am pretty sure that it is my u-joints, even if it isn't I am just going to go ahead and replace them anyway.

tommudd · **Posted:** Fri Feb 18, 2011 1:08 am

Yes that is your u-joints
that clip you see in there has to come out and then you take them out. Large vice works, or have had to hammer them out on the trail before
Not a hard job if you know what to do

Scottm2010 · **Posted:** Mon Feb 21, 2011 12:29 am

Ok, thanks. I am going to have someone in my local club help me this week and get them both replaced.

Hopefully it is just the u-joints that is causing the problem. I've done some looking around and I think they are the problem. If not, it doesn't hurt to replace them anyway. Haha.

Scottm2010 · **Posted:** Mon Feb 21, 2011 7:57 pm

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

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.

Weird Vibrations

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