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

[KMeloney]

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.

No, I dont. And again, mine is a heavy thud. Nothing metallic about it.

 

[adventurenali92]

Just a thought…. Even though @KMeloney said no engine replacement in his truck, not a bad idea to check the transmission cross member bolts.

I say this as when I did my last oil change on my 2006 XL a few months back, the filter fought me coming out, and going in as it always does. I was so fed up that the K&N “easy install nut” on the bottom of the filter still didn’t have enough room to clear a socket properly secure on the nut to remove with a ratchet on it that I pulled the cross member out to make room and get the filter out. I snugged everything back down proper when I reinstalled it after the filter went in, but last night while doing my oil change, the bolt on the drivers side of the cross member was over halfway loose and the crossmember could travel quite a bit up and down on that side. I didn’t notice any abnormal noises but that doesn’t mean it wasn’t making any if the crossmember was moving. I’d imagine though that sitting in the drivers seat and hearing that cross member slap around, it would sound as if something was hitting the underside of the truck just to the rear of the drivers seat area.

 

[337Bengal]

I am glad someone has this issue. I have a 2023 Tahoe RST 6.2 and hear the same thud coming from under the rear seat area. I installed a sub last year and thought maybe that was it… like a loose wire or something making it pop. That’s not it though. I need to bring mine in for a recall. Gonna ask them to look into it. Worries me when I hear it. Problem is it’s just so random.

 

[KMeloney]

I am glad someone has this issue. I have a 2023 Tahoe RST 6.2 and hear the same thud coming from under the rear seat area. I installed a sub last year and thought maybe that was it… like a loose wire or something making it pop. That’s not it though. I need to bring mine in for a recall. Gonna ask them to look into it. Worries me when I hear it. Problem is it’s just so random.

Please keep us posted!

Maybe don't direct the techs to a certain area of your truck where you think you hear the noise. I directed the tech to look somewhere around the rear axle, but I don't really know that the noise it coming from there. It might actually be coming from somewhere up front, as others have experienced. But we're all not losing our minds, I'm sure. Someone has to be able to track down the source -- and maybe that source in my truck will be a crossmember bolt being loose, too.

 

[tahomie]

My 23 Yukon SLT definitely has something similar happen around just behind the driver’s seat from time to time. Almost sounds like a nut rattling around. Happens very infrequently.

 

[KMeloney]

I am glad someone has this issue. I have a 2023 Tahoe RST 6.2 and hear the same thud coming from under the rear seat area. I installed a sub last year and thought maybe that was it… like a loose wire or something making it pop. That’s not it though. I need to bring mine in for a recall. Gonna ask them to look into it. Worries me when I hear it. Problem is it’s just so random.

Anything more on this?

The more I think about it, I'm thinking that in my situation it might as well be a loose mount/crossmember, as mentioned earlier. It just doesn't seem to coincide with the suspension rebounding, say, so I'm thinking it's a loose bolt allowing play in something heavy under the truck...

 

[Yarbrr1]

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.

Hello - I wished I had seen your post earlier, as I posted today separately with the EXACT same issue you are referring to. Mine is a 2023 Tahoe High Country, and you described the noise perfectly. In fact yesterday, my wife was with me when the sound occurred, and she asked, “what in the hell was that?! It is both a deep thumping noise that literally startles you, and she could also feel the impact from her passenger seat. She said it felt like it was right behind my drivers seat. Each time it occurs I think I hit something in the road, which of course I didn’t. For me, it seems to occur when I’m driving a straight road, and it has occurred at varying speeds from 40/45 to over 60 or so.

Does anyone know if there are any GM engineers that read this forum? I’ve had Corvettes over the last number of years, and those engineers contribute to the Corvette Forum from time to time. I have owned MANY GM Yukons and Tahoe’s and this has NEVER occurred to me.

 

[KMeloney]

I'm thinking it's the loose crossmember situation that someone posted about previously. Maybe. Just still not sure!