I have read a good amount of posts on this topic. Usually track bar hitting a spring, loose shock bolts or worn sway bar connects. The previous owner of this Jeep spend good money chasing this clunking and found nothing. I just swapped in Rubi axles so everything is correct and torqued. All hardware is grade 8 9/16th or metric 10.9. Jeep has 84K miles and has not been an offroad vehicle in the past. Rear control arms are stock. It is not the tire carrier that is clunking.

Here is my thought... Could the control arm bolt holes be worn out (oval) from the original threaded factory bolts? Has anyone experienced this? I really thought that after the 9/16th bolt replacement that the clunking would finally be gone!

 

I've had slightly undertorqued control arm bolts before so I know that sound, and it would be the same with an ovaled out hole. It would be a single clunk each time you change direction forward/backward, and you would be able to reproduce this sound at will. I would have a hard time seeing one of those bolt holes getting wallowed out though as it would take a lot of repetitive shaking forces to do so IMO. If you think about a track bar hole getting wallewed out soemthing like that can make more sense cuz a bad wobble is a lot of horizontal shaking back and forth hammering a way at frame side bolt and a wimpy bracket. You're never experienceing that same sort of force on a rear control arm (forward/backward for that application).

Few troubleshooting questions:
- can you reproduce this sound at will?
- if not, can you determine precisely situations that are triggering it or is it completely random?
- is it a single clunk, repetitive, random, rotational?
- does it happen on flat road or only as you're turning up/down an incline (think body rolling and suspension flexing)

A good way to check for suspension related noises in back is just get on one side of the jeep in the rear and push that sucker back and forth. you can really get that thing rocking and it will highlight a lot of suspension sounds. Have you checked torque on sway bar links? Those can often cause a clunk when the body rolls even just a little bit.

 

Thank you. This is not a sound that can be reproduced at will. The sound is absolutely tied to the surface roughness of the road. It is not rotational nor tied to forward or reverse travel. Only a rough road patch will produce this. The sound is similar to what I would expect from a loose shock absorbers. The shocks are relatively new. The rear sway bar links are new. Not certain if they were specifically torqued. The exhaust is tight. The tire carrier is tight. The jack and tools are not loose. There is no back seat. This is a significant noise over rough ground. I would expect to hear this noise if the rear shocks were both blown out.

 

That certainly does not sound like control arm bolts to me. I know this sounds old school, but troublshooting and tracking down often is just narrowing location. If that were my jeep what I'd do is have someone else drive it while i was in back trying to listen and at least narrow down general location. I'm lucky enough to live around all sorts of crap roads to test this stuff on though. If you have an old cell phone I'd even go so far to tape/zip tie in areas on the underside to try and video or just record audio to help determine general locations it's louder. Obviously something that if you did lose on the road it wouldn't be a big deal.

If you didn't already, at least go push the hell outta that thing and get it rocking. That will at least be moving the rear suspension. If you have a 2nd person have them help.

 

Yep. That is my plan. We have dirt roads around our house. Will have my wife drive while I lay on the floor in the back.

 

Remove what you can EG rear sway bar and spare tire, and see if there is a difference. What about taking the rear driveshaft off and making the Jeep front wheel drive for 20 minutes to see if the problem is there.

 

Yes, a sway bar-disconnected test drive would prolly be a good idea.

 

I know you mentioned the tire carrier being tight, as well as tools, jack, etc. How about that tailgate latch? those tend to cause noises sometimes. It would be a "clunk" sound as well.

 

Thank you RwH. The tire carrier presses against the tailgate with some force and is quite stout. My CJ7 had a rattling tire carrier, so it is a sound that I am familiar. My rattling/clunking is in the suspension.

 

No noise produced from rocking that back and forth as suggested?