I have had a thud noise for some time. It started after I installed a Daystar 1" BL. It comes from the rear when I go over larger bumps in the road. Particularly bad when I go over a couple of bumps one right after the other. I also have a Teraflex 2.5 BB, but it was doing this before that install. Here is what I've done so far: 1) took out BL and re-installed 2) removed jack 3) inspected rear door and appears to be closing correctly but did not adjust striker plate 4) inspected track bar and not hitting anything 5) I don't believe it is bumpstops - bumps are not that big when this sound occurs, but it is definitely coming from the rear- somewhere from the springs back. 6) Nothing appears abnormal about shocks/seats 7) inspected everything underneath to see if there is any evidence of marks where something is coming together. When the noise it occurs, it is like two heavy objects coming together...sometimes it will be a thud thud thud like something is loose and are banging together until the energy dissipates. Daystar has no clue. All the body mount bolts/isolator nuts are torqued to spec. Any suggestions would be greatly appreciated.

 

Also checked gas tank which appears to be solidly in place as well....grrrrrrrrrrrr. I also grinded down the back two washers back when I installed it because I was getting that annoying squeak, but since I did that, the squeak is gone, but I am left with this thud still coinciding with bigger bumps in the road.

 

Man this thread needs help!! Bump....

 

have you made sure that your rear track bar bolt at the frame mount is not making contact with your bump stop extension?

 

I have had this issue twice, both shock related. The first time it was the rubber groument in the shock, the second time I broke the shock mount. Hope this is your problem they are both easy fixes, but the thud will drive you crazy until you fix it.

 

Yes, what he said! ... I had the same issue from the sounds of what you are experiencing. Is the noise on the right rear side? My bolt was hitting the bump stop on the axle no matter which way we flipped the bolt. We had to cut a piece off of the bump stop so the bolt clears it.

 

I got my work cut out for me. Thank you all for the responses. Sorry it took me awhile to respond, I work 13 hour shifts and the last few days have been especially raunchy. Time to get serious and find this thing.

 

Bimmer - the exhaust can hit the bumper but it makes more of a hollow tinny sound...but from inside the vehicle that could be it - it could sound much differently from the cab. I'll cushion the possible contact point to see if that makes the difference. TY.

Jdk - the shock grommets appear normal and the shocks are brand new with no significant heavy wheeling on them as of yet. Mounts are def intact. On your first prob, did the grommets look obviously worn/damaged?

Mtra - Ive got to know these suspension components a bit better - my first Jeep/4WD vehicle. I assume you are referring to the track bar mounting bolt? I'll look again...you are not the first person to suggest this as an issue and I am very suspicious here. Unfortunately, due to my inexperience, I'm not seeing how that bolt could come into contact with the bumpstop components even at full stuff. But again, Ive enlisted the help from 2 other folks in pm's that have suggested this is where I should start looking at, especially with a Teraflex BB.

Great learning experience, annoying as hell in the process of. Thanks to all of you for the responses. I'll let you know what I find.

 

Gromments looked good from one side but had the other side missing. just grab the shock at the bottom yank it back and forth do the same to the top, if it feels secure that's not your problem.

 

So I took a few pictures. I am hoping I could get some more feedback. I have a new theory on my thud issue. The one picture is of the rubber bumper on the tire carrier. With a help of a friend who works at a 4wd shop, we were able to pull the tire carrier away from the door enough to possibly cause it to bang against the door on bumps. Not to mention the fact that I am still running the more lightweight OEM wheels/tires, and the carrier is designed for a bigger wheel, which would help to weight it down a bit more in back. So, I am going to move the striker plate on the bumper a tad bit more forward so it closes tighter thus pushing the bumper up against the door harder. I am also going to place another washer or two under that rubber bumper just to ensure it is as tight as I can get it with the OEM's. This is my first area of suspicion.

The other pix are of the passenger side track bar mount bolt. Again, even though the bolt is facing forward, I don't see how that is going to come into contact with the bumpstop plate. And there are no signs it has been hitting.

The other is the distance between the muffler/exhaust and the frame. Considering how little it takes to provoke the sound, it seems this is okay. The grommets are intact. The shocks are solidly in place, so again, not my first suspicion.

I will be working on this tomorrow, along with a couple of other mods, so wish me luck. Thanks for any input.