"Clunk!" noise in the rear when hitting bumps

cmassey_2006 · 08-19-2006, 12:44 PM

Hey guys, I tried searching but apparently it must not be working right now cause I get prompted to download the 'search.php' page when clicking search.

...Anyways, sometimes when I hit a big bump in the road, go over speed bumps, etc. there is a very noticeable "clunk" sound that comes from the rear-end of my Jeep. It usually only happens when the impact is a quick jolt. My first thought was something was loose (like the shocks) , so yesterday I re-checked the torque of every bolt in the rear (leaf springs, shackels, shocks) and everything is tightened down to factory spec. I then thought it was the junk in my rear cargo area (spare, tow straps, tools, etc) and removed everything, but the sound is still there. It just concerns me because it wasn't there before I installed my lift and I want to make sure it isn't a sign of something loose or about to break. The only suspension-related changes I made in the rear since the noise were new leaf packs and shocks, and I remove the rear swaybar.

Has anyone had this problem and could let me know what caused the noise?

The next thing I am going to try is to have a friend drive my jeep slowly over a speed bump and see if I can pin-point where the noise is coming from. I'd be greatly appreciative of any help!!!

cmassey_2006 · 08-19-2006, 05:44 PM

*bump*

One last request for ideas, please. Thanks!

91xjgawes · 08-19-2006, 05:51 PM

mine sometimes does it to my dad said it was nothin to worry about somthing with the rear end, thats been 20000 miles ago, sorry i couldint be more help

anony91xj · 08-19-2006, 06:01 PM

What exactly did you install for the lift?

Could be bushings on either end of the leaf springs, shock bushings, a broken spring or a bad shock...

cmassey_2006 · 08-19-2006, 06:04 PM

Quote:

Originally Posted by anony91xj

What exactly did you install for the lift?

Could be bushings on either end of the leaf springs, shock bushings, a broken spring or a bad shock...

For the rear, I installed new RE 3.5 leaf packs and new OME shocks. Do you think some BPE's will help?

redyouch · 08-19-2006, 06:17 PM

probably your exhaust hitting the body in some location

truckin6382 · 08-19-2006, 06:31 PM

My exhauset rattles against the frame and the rear shackle.

anony91xj · 08-19-2006, 06:57 PM

Quote:

Originally Posted by redyouch

probably your exhaust hitting the body in some location

Could be that as well. What's a BPE?

anony91xj · 08-19-2006, 07:10 PM

Quote:

Originally Posted by redyouch

probably your exhaust hitting the body in some location

Could be that as well. What's a BPE?

bogger jeep · 08-19-2006, 07:37 PM

your rear shackle comes back when you hit a bump causing it ti hit on the rear frame rail. this is more likely if your springs all worn , which causes them to lay flatter. if you look there is only about an inch or less of space between the shackle and the rear frame cross member.

cmassey_2006 · 08-19-2006, 08:30 PM

Quote:

Originally Posted by anony91xj

Could be that as well. What's a BPE?

Sorry, it stands for Bar Pin Eliminator: http://jeephorizons.com/tech/jksbpe.html

bogger jeep: I thought about that as another cause, after re-checking the torque of all my bolts in the rear. I guess I could put color chalk all over the shackles and see if the chalk gets transfered to the frame rail after the next "clunk". Good idea.

redyouch: My exaust never gave me any trouble before the lift, but that doesn't mean it isn't just a coincidence. See, this "clunk" noise started happening right after I installed my lift, so my first thoughts were the changes I made in the rear. But I'll check that too, thanks!

Thanks everyone for your help so far, I think my next step would be for someone to reproduce the noise with my XJ while I stand outside and watch the rear. I'll let you guys know what I find, if anything. I really appreciate your help!

bogger jeep · 08-20-2006, 06:56 AM

grease may be better chose to put on the point where it may hit. come nearer getting onto the frame. thats where mine was hitting.

cmassey_2006 · 09-05-2006, 10:03 PM

Hey, just wanted to update this thread. I removed my leaf packs this past weekend and greased the bushings and bolts real well. The noise has gone away and the rear of my Jeep is noticeably softer in ride quality because my shackles flex more easily now. Thanks for everyone's help. And thanks Balloo for your help in my other thread about this. I did finally get to test out my new lift this past weekend after resolving this issue and it performed very well and I had a blast! Thanks again!

BskisTJ · 09-05-2006, 11:35 PM

Do you have larger aftermarket shackles?
This was one of my noise problems as well. I had RE shackles and found that the two of the stock rear bumper bolts were hitting the shackles. I drilled out nuts for the bumper bolts in the rear crossmember and put in larger shorter bolts. This helped with the noises in the rear, didn't hit the shackles anymore. Would check exhaust as well.

cmassey_2006 · 09-06-2006, 12:05 AM

Quote:

Originally Posted by BskisXJ

Do you have larger aftermarket shackles?
This was one of my noise problems as well. I had RE shackles and found that the two of the stock rear bumper bolts were hitting the shackles. I drilled out nuts for the bumper bolts in the rear crossmember and put in larger shorter bolts. This helped with the noises in the rear, didn't hit the shackles anymore. Would check exhaust as well.

Nope, just the stock shackles. And my noise has gone away. After greasing them up it got me thinking about investing in some greaseable aftermarket shackles. But things are great now, so yeah.