Chasing the clunk

[Pilsner]

So another round for me. Last time I found a front lower control arm bolt loose. This time is proving more difficult. There is a metal on metal sounding clunk in the rear. Probably getting louder after a couple weeks wheeling in CO. If I hit the gas forward with some gusto, I get a clunk immediately. It is then fine until I brake hard or reverse, when I get a second clunk and then it will repeat forward. So there is something alternating/flipping back and forth. It reminds me of the sound you get when leaf spring U bolts are loose and the axle can rotate a little under torque. I laid under the bed and had my brother drive forward. I can hear it plainly and it's pretty loud, but can't find it. It sounds superficial and the way it toggles, I am guessing it isn't tranny or transfer case. One end link bushing is certainly lose and allows the end link to move between the washers, but I don't think is the issue from where the sound appeared to be coming from. To be safe, I'll pull both end links to test. All bolts felt tight everywhere in the rear. I will also pull track bar to test. That really leaves control arms and springs. Control arms make the most sense to me, but they don't have any play and the bolts are tight. I may put an impact on everything and make sure they are damn tight. Anything I am forgetting?

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[Renegade]

Rear sway bar link at the frame. It’s common, and causes that sound.

 

[Pilsner]

Just slop allowing to shift? The design of the bushing these is...not great. The metal spacer/sleeve that goes over the bolt is long enough that tightening the bolt only tightens against that sleeve and does not allow you to put any pressure on that bushing to take the play out. I'll pull them and test.

 

[JTnw96]

I have this issue if I off-road a lot, I just tighten up the sway bar links and the sound goes away. I've learned to just to check and tighten them up every few months now.

 

[Pilsner]

I have this issue if I off-road a lot, I just tighten up the sway bar links and the sound goes away. I've learned to just to check and tighten them up every few months now.

What links do you have? Mine are from Readylift and the sleeve is longer than the rubber bushing around it, so you can tighten them, but it never tightens the actual end link. I'm going to pull them when the rain stops and make sure that's the noise I have and replace them. Both sides have a lot of play and you can slide the end link across the busing with very little effort.

 

[JTnw96]

What links do you have? Mine are from Readylift and the sleeve is longer than the rubber bushing around it, so you can tighten them, but it never tightens the actual end link. I'm going to pull them when the rain stops and make sure that's the noise I have and replace them. Both sides have a lot of play and you can slide the end link across the busing with very little effort.

Clayton Off Road. The bushing end is what I have to tighten every so often. When its loose I can literally just rattle it.

 

[bertio]

For anyone else chasing a rear end clunk on acceleration.

I found my rear springs had jumped the rubber isolator perch just enough to cause a clunk. Was able to find it by wiggling the springs and replicated the sound.

$30 for new isolators, dropped the springs and positioned them with vinyl tape to keep them on straight during the reinstall. Clunk gone.

 

[Pilsner]

For anyone else chasing a rear end clunk on acceleration.

I found my rear springs had jumped the rubber isolator perch just enough to cause a clunk. Was able to find it by wiggling the springs and replicated the sound.

$30 for new isolators, dropped the springs and positioned them with vinyl tape to keep them on straight during the reinstall. Clunk gone.

It sounded to me like my noise was not the end links, but it's hard to tell with someone driving away quickly as you lay underneath. I'll check this too. I'm hoping for end links. Dropping the rear enough to fit 4" lift springs is a pain in the ass. I do have extended brake lines now, so that should help.

 

[Pilsner]

Clayton Off Road. The bushing end is what I have to tighten every so often. When its loose I can literally just rattle it.

Those are what I was looking at. I like the heims and the adjustability.

 

[Pilsner]

Just to follow up. Finally got the clunk fixed. It was a rear lower control arm bolt. It was already tight, but not enough. I would guess it was at 70 ft/lbs. It went about 1/2 to 3/4 turn to my calibrated torque hand at 130 ft/lbs. If you have a clunk in the rear with forward and reverse movement, control arms are on the list to check. Now on to the next noise.

 

[ttn333]

Just to follow up. Finally got the clunk fixed. It was a rear lower control arm bolt. It was already tight, but not enough. I would guess it was at 70 ft/lbs. It went about 1/2 to 3/4 turn to my calibrated torque hand at 130 ft/lbs. If you have a clunk in the rear with forward and reverse movement, control arms are on the list to check. Now on to the next noise.

Got the clunk toward the rear passenger. Told myself to retighten all control arms but somehow I got lost in the weeds and decided it was the rear endlinks that needed replacing. A couple of days later and a couple of hundreds spent (for next day air shipping), clunk was still there. This morning I took my torque wrench to all the nuts/bolts, turns out the rear passenger side lower control arm frame end bolt/nut needed 1/4" turn to get to 120 ftlb. On the bright side, the endlinks probably needed replacing anyways. Got almost 60k miles on them the joints are pretty loose. Preventative maintenance.

 

[AstroZombie]

If it sounds like a leaf spring clunk why haven't you checked your leaf springs?

 

[ttn333]

If it sounds like a leaf spring clunk why haven't you checked your leaf springs?

Exactly! KISS.

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