slow speed suspension clunking

kpanza · July 25, 2020

So, all of my leaf spring bolts were to spec, both at shackle end and fixed end. But one thing that I did notice, was the passenger side front mount...the bushing is torn and looks too compressed on the outside edge. The inboard shoulder of the bushing is about 1/4" thick and ok...but the outboard shoulder is less than 1/8" thick and has a tear? It's weird, the inboard part of the leaf spring mount extends to just past the bushing edge...but the outboard part of the mount, it's too short for the bushing. The lower edge of the bushing is not supported by the metal mount...seems to be a design flaw. I will have to wait til I can get someone to help me rock the truck while I lay under there watching that bushing...really hoping that the leaf spring eye is not making metal on metal contact with the mount!!

topgear1224 · July 25, 2020

So, all of my leaf spring bolts were to spec, both at shackle end and fixed end. But one thing that I did notice, was the passenger side front mount...the bushing is torn and looks too compressed on the outside edge. The inboard shoulder of the bushing is about 1/4" thick and ok...but the outboard shoulder is less than 1/8" thick and has a tear? It's weird, the inboard part of the leaf spring mount extends to just past the bushing edge...but the outboard part of the mount, it's too short for the bushing. The lower edge of the bushing is not supported by the metal mount...seems to be a design flaw. I will have to wait til I can get someone to help me rock the truck while I lay under there watching that bushing...really hoping that the leaf spring eye is not making metal on metal contact with the mount!!

The leaf springs have to be able to twist otherwise they'll break if you for instance start sliding and then suddenly catch traction

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dannyandrus · July 28, 2020

Senior Advisor at GMC sent me back to the dealer. Shop foreman advised that it may be the leaf springs and because it was out of warranty, would cost me to replace them and that there is no guarantee that it would fix the problem. Since it was just out of warranty, GMC offered to pay a substantial part of the replacement but my part would be just under $300. I'm not going to pay $300 on a "maybe". Of course, if it would have been a driveline problem as I suspect (differential), it would still be under warranty. Waiting on GMC to call me back because they would like an engineer to look at the truck. Will advise of what he tells me.

LS3GXP · July 28, 2020

If you have the same lateral movement of leaf springs as most, and as I do, I definitely wouldn't pay to replace the leaf springs. My brand new springs popped and made noise the day they were installed but only slightly. The dealer greased them and told me this was part of "normal" maintenance and there wasn't anything else they can do. It's been a week including one day of driving in rain and the new springs sound as bad as I've ever heard them.

robstitzer · July 31, 2020

Glad I found this thread.. I just leased a 2020 Sierra Elevation and I'm hearing the same issue every time I back up my driveway into my garage. Low speed, on an incline upwards. The clunk in the rear of the vehicle. I thought I was nuts.. I traded a 2019 Trail Boss LT in for this and it didn't make any sort of sound at all. Ugh...

kpanza · July 31, 2020

Yeah, this is a weird one. Seems like it affects trucks across the trim levels, max tow and non-max tow, etc. My '20 SLT 4x4 w Max Tow has done it since day 1, but it actually sounds like it is getting louder and happening more often, am now at 1900 miles.

lapoolboy · July 31, 2020

TSB # 19-NA-129. Solves the issue completely. Good day.

kpanza · July 31, 2020

If you have seen other posts and threads, this TSB has NOT solved the issue for many owners...

LS3GXP · July 31, 2020

5 minutes ago, kpanza said:

If you have seen other posts and threads, this TSB has NOT solved the issue for many owners...

+1 Didn't resolve here either.

Update to ealier post: GM customer "care" escalated our case from the initial call and said we would hear back early this week, never called. We contacted them Wednesday evening and left a vm. The call we received back was they were closing our case and to let me know if we were still experiencing issues. What a joke. We're selling and are done with this apathetic posture by GM.

lapoolboy · August 1, 2020

6 hours ago, kpanza said:

If you have seen other posts and threads, this TSB has NOT solved the issue for many owners...

Then their noise is being caused by something else.

topgear1224 · August 1, 2020

+1 Didn't resolve here either.
Update to ealier post: GM customer "care" escalated our case from the initial call and said we would hear back early this week, never called. We contacted them Wednesday evening and left a vm. The call we received back was they were closing our case and to let me know if we were still experiencing issues. What a joke. We're selling and are done with this apathetic posture by GM.

I have vastly different issues. Was gonna trade to a different brand.... But they offered $32k on a $58.8K MSRP truck with 5k miles........

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kpanza · August 19, 2020

My truck is in the stealership getting the TSB done right now, for the rear suspension clunking (bowling ball effect)...will post up if it works when I get the truck back. Been a GM guy all my life, but am starting to lose the faith - they gave me an Escalade ESV for a loaner, and after I get the baby seats loaded in, all my stuff, I fire it up to leave...dashboard lights up with all kinds of error messages about steering assist, stabilitrak, you name it...so they go scan it, clear it, have no clue why it's happening. Since I only work about 4 miles from the dealer, they say "just take it, we are sure it's just some computer glitch"... ha! Sure enough, a mile down the street, error messages galore. Unreal.

kpanza · August 19, 2020

Well, I am happy to report that the TSB made 90% of the clunking/bowling ball noise go away over bumps, backing out of driveway, etc! I say "90%", because if I turn off the radio AND A/C, and hit the same spots that made it clunk like crazy before, I can just BARELY make out the noise. So, count me in the lucky ones that this fix seems to work for.

Now the real test will be does it LAST going forward? Or will it come back...stay tuned, will update my findings as time goes on.

leverett.scott · September 5, 2020

Just had the new pads put on my spring as well, seems to be working.

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Davestruck · September 16, 2020

On 3/21/2020 at 5:04 PM, Gthompson said:

I'm having some issues with my brand new AT4. Just purchased a 2020 AT4 (2 weeks ago), had 24 miles on it. Within 100 miles it started making a clunking sound under the bed. Another 50, the steering started pulling and I had to take it in. Took it in and they tightened the u-bolts for the leaf springs which fixed most of the problem. The issue I still have is an annoying clunking sounds somewhere towards the middle of the truck, all the time. Happens at every stop sign, every turn, every speed bump. It's driving me crazy. The last time the dealer wouldn't even take it in. They said, "let us do some research before we bring it in." The suspension definitely doesn't feel like it did day 1, feels a lot "looser" and the clunking sound is tough to deal with.

Anyone having similar problems? Find a fix for it?

Thank you!

Just had mine into the dealer. Same thing. U-bolts under torqued, apparently...Seems better now...I have a 2019 Elevation...15,000kms on it