GMC denali yukon 2022 mysterious noise sounds like something hits underneath car behind drivers seat

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bscottal

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Even since purchasing my new 2022 GMC Yukon Denali, it has randomly made a knocking noise under the car behind the drivers seat. It sounds like something gets thrown up and hits underneath the car. It can happen under 30 MPH or on highway at 55-65 MPH. It is startling and loud enough to take notice. Anyone know what this is? The dealer hasn't been able to replicate and doesn't know how to fix.
 

KMeloney

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I asked my dealership to look into something maybe being loose under my truck for the exact same reason (and they, too, said they couldn't replicate the condition).

For me, I think it's rear-suspension "rebound" related, but I'm not positive. I've noticed it most when making a turn through an intersection after hitting a dip in the road. It's like medicine ball is slamming against the underside of the truck, and I swear I can hear and FEEL it.

It's not metallic-sounding, right? Is it like a heavy, dull "thud" sound/feel? And you don't ever feel it just driving along down a smooth, straight road, do you?

I hope others chime in on this thread and that we can get to the bottom of it.
 

DontTaseMeBro

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Do you know if the engine was replaced? My 2022 had its engine replaced and the tech at the dealership didn’t torque down the crossmember bolts down all the way. Dealt with an absolutely annoying clunk on turns for months before I was able to find what it was with my current dealers help.
 

KMeloney

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Mine is a year old and hasn’t had the engine replaced.

…and this feels like it’s around the rear axle somewhere.
 

fondupot

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I asked my dealership to look into something maybe being loose under my truck for the exact same reason (and they, too, said they couldn't replicate the condition).

For me, I think it's rear-suspension "rebound" related, but I'm not positive. I've noticed it most when making a turn through an intersection after hitting a dip in the road. It's like medicine ball is slamming against the underside of the truck, and I swear I can hear and FEEL it.

It's not metallic-sounding, right? Is it like a heavy, dull "thud" sound/feel? And you don't ever feel it just driving along down a smooth, straight road, do you?

I hope others chime in on this thread and that we can get to the bottom of it.

Check the spare. Maybe it's not cranked up enough, and is bouncing around under there.
 

KMeloney

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I really thought/think that maybe my spare is just loose enough to bang against its housing in different driving scenarios. (But that's with having no real sense for the actual arrangement of the spare tire compartment.)
 

KMeloney

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Check the spare. Maybe it's not cranked up enough, and is bouncing around under there.
I specifically suggested to the dealership that I thought that's what it could be -- and they said they checked it and didn't find anything. I can't say whether they actually checked it, though.
 

WalleyeMikeIII

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Got any loos items stored under your rear floor in the cargo area. My dealer threw the lug nuts in there after installing the locks…and they made noise under certain stops/turns, etc. I actually lined my under floor storage with neoprene (mouse pad like material) from the fabric store.
 
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