Name this noise!
 

It's a clunk. It comes from the rear, driver's side wheel. Possibly both rear wheels? Makes it's sound when going over medium bumps. It sounds like the axle is hitting the limiter bump stop. Probably was over a year ago but I put new springs, added air bags (for when I load 'er up) and put new shocks on all the way around. I think I originally wondered what the sound was and noticed the sag and measured the drop of my 4R, so upgraded those things and now have a much nicer ride and definitely higher (2-3 inches) but notice I still hear this clunking over bumps and now it's annoying since I know the stops definitely have clearance now.

What it isn't -

1) doesn't seem to be the exhaust pipe. It is close in clearance over the rear axle but I've heard a tailpipe hitting before on another vehicle and this doesn't sound like that.

2) not the spare tire. Honestly thought I was onto something when I removed it and found it was light on air... sooo, thought maybe the low air was causing the wheel which was wound up when it was full, to rattle around a little under there over bumps due to lower pressure in the tire.

3) even though shocks are only a little over a year old, lifetime warranty so went ahead and figured a faulty shock and replaced.

4) all suspension parts "appear" to be intact. no broken parts.

5) for sh*ts and giggles, I have tried both extremes for my air bags... completely deflated and completely maxed out - no difference in noise.

Soooo, ideas of what the noise is or some processes I can take to continue ruling things out? Unfortunately the only way to test it is to drive and run over bumps... Seems a suspension issue. Hoping for a quieter ride. This noise has not been with the vehicle the whole time I have owned it.

How strong is it, can you feel it? Do you notice it at all speeds or just going slower? I recently just lifted as well and I'm also trying to tackle to new noises one by one myself. I have a pretty decent pop/clunk from my sway bar, it's more so when the body begins to roll (thus working the bar), but I have noticed it over some sharp bumps, but if your noise was pre-existing to the lift it probably wouldn't be the sway bar (if it feels like its RIGHT under your driver's seat, it might be). I also have an annoying squeak that I suspect to be the drivers UBJ or LBJ, which could be your culprit.
It's more than likely a bushing, but could also be a ball joint. Check any of the bushings to see if the holes have been stretched or egged out, even a little bit, and check your BJs and see if they're wet. Does it sound like a rubber or metal clunk? (maybe take a video if you don't know). The thing is they dont necessarily have to appear broken or look different at all for parts to fail - as they age they tend to wear in a specific fashion, and when you begin to mess with the lift you're now causing parts to work and wear at a totally different angle than before, and this can really expedite their need for replacing. This goes for pretty much everything on a car - from the U-Joint bearings to the control arms to the rubber bushings holding everything together.
If you haven't done your ball joints/control arms I'd seriously look into it, but first check out the bushings. If it doesn't go away, at least you know you're not potentially risking a crash and have fresh components. What lift did you go with anyways?

gas tank banging off the skid plate. check the rear strap, it’s prob rusted off...


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On my list to rule out, assuming it’s in the rear as you suspect.

1a. Did you loosen sway bar bushings while installing the new, taller springs? Even if they are not your culprit, should be loosened (lubed if your feeling froggy,) then re-torqued with the vehicle on the ground... suspension loaded. This puts the bushings in a relaxed state at your normal ride position.

1b. Same for panhard bar

2. Also check your sway bar end links are properly connected and or not broken.

3. Check shock top nuts are still tight


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Thanks for replies. First, never said lifted. New springs just put truck back to normal height. Tried looking at all bushings, did replace rear upper control arms a few years ago and saw what a bushing that appears normal looks like after removal and seeing it's cracked, dry rotted. Hence the quotes around "appear". Great suggestions and will take the next day or two to see what else I can see. Originally before replacing springs and shocks, was definitely hitting the bump stops above the axles and that may have been a slightly different sound (or maybe that doesn't make a sound at all) than now because there is no way I am hitting them now. But it sounds the same and possibly the sound I heard before was the same issue that was caused by worn suspension parts?

It's a ca-clunk when going any speed and no noticeable affect on driving. Can feel it. It feels like the rear axle is slamming the underside of the truck IN THE BACK. Definitely not a soft, springy feel over medium bumps. Small bumps feel fine, just those little larger ones that you hear and feel it.

Not conclusive YET, but I'm aiming towards naming Ron Burgandy a winner. The gas tank can be pushed up and let down about 1/2 to 1 inch and seems logical to be the issue since it does seem to be a noise on the drivers side. With that said, the strap appears to be fine and there does not seem to be any way to tension it more to reduce the possible bouncing. I have not taken the skid plate off to actually see the strap but looking through the holes of the skid plate where I can does not lead me to believe it isn't holding the tank. Ideas? put a piece of 1/2 inch trex material under there between the skid plate and tank?

Also being considered runner up is end links for sway bar, they are connected and appear to be ok but the rubber seems torn near the bushing sooo, for an inexpensive thing to cancel possible future issues, being replaced.

Exhaust is awfully close to the rear of the body over the axle so I squeezed a piece of wooden broom handle, 4 inches of it in the rubber hanger of the tailpipe to give another couple inches drop for the tailpipe. Only other way I can see to help that is to take the tailpipe off and bend it somehow. Again, don't think it's an exhaust thump. Strongly leading towards the tank being the issue!

Soooo, 2 years later, I still have the noise, use the truck only occasionally... starting to get used to it :-( After a couple different mechanic shops - one that said the drive shaft might be a little loose and so they tightened up the pinion gear. I didn't notice much difference... (and they probably wouldn't have either if they took it for a test drive? Another shop I then took to because the first shop didn't figure it out and suggested replacing front wheel bearings because of a separate noise, growl in the front. So second shop replaced/pressed in new bearings, still hear a growl, guessing maybe bearings in front diff? But second shop merely said, "yeah, it's a little noisy over bumps" and that was it....


Sooo, present day, a friend suggested I bring it to his shop and lets look at it up on a rack... we looked around, hung on some stuff... FINALLY, BODY MOUNTS!!! Sooo, I think that explains it and didn't take us long, sheesh... I ordered some new rubber bushings and will begin the process changing those out on the back as well as one in the middle of the frame...

Just wanted to come back to this post and answer in case others haven't checked their aging mounts and have noise, clunking going over bumps. No one here suggested it and it was quite easy to see when I looked at the rusty mounts and felt above them that the rubber was a bit tattered.... I will start a new post to see if others have input on how to easily change at least the two at the rear on either side.. Look for the post, "Aging Body Mounts".