Thump in floorboard can’t fine source

[Ponchonutty]

so I’ve been chasing this odd thump when going over unlevel terrian. Mostly seems when the chassis flexes I get what I describe a sound as if someone is hitting the floorboard with a heavy hammer. It doesn’t do this all the time. Mostly when say pulling into a driveway at low speeds. All shocks/struts are new as well as sway bars and endlinks. Anyone else have experience like this? Truck has 185k miles on it and this has been doing this for about the last 10-12k miles

 

[RED TAHOE LS]

Year, Make, Model, 2wd, AWD ?
David g..........

 

[HiHoeSilver]

so I’ve been chasing this odd thump when going over unlevel terrian. Mostly seems when the chassis flexes I get what I describe a sound as if someone is hitting the floorboard with a heavy hammer. It doesn’t do this all the time. Mostly when say pulling into a driveway at low speeds. All shocks/struts are new as well as sway bars and endlinks. Anyone else have experience like this? Truck has 185k miles on it and this has been doing this for about the last 10-12k miles

Check the control arm bushings and ball joints.

 

[Ponchonutty]

Year, Make, Model, 2wd, AWD ?
David g..........

2008 AWD Denali

 

[Ponchonutty]

Check the control arm bushings and ball joints.

I have before but couldn’t find anything. My past experience with ball joints and control arm bushings is you’ll hear it when turning sharp or bumpy roads. This is quiet. Only when you feel the chassis flex is when the thump happens

 

[kbuskill]

Check all your body mounts.

 

[Ponchonutty]

Check all your body mounts.

Yes. This is next plan once the weather is decent so I can pry around. Last visual inspection I didn’t see anything. If they aren’t too much I may just replace them anyways

 

[mtl111]

I'm assuming your truck has torsion bar suspension, if so check the rubber mounts that are inside the brackets at the rear of the torsion bars. I've found these to cause thumping/rattling noises even when they "look" ok. They get worn and allow up and down movement of the torsion bars. Use a prybar to check for any small amount of movement. Let us know what you find, good luck!

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[mikeyss]

I'm assuming your truck has torsion bar suspension, if so check the rubber mounts that are inside the brackets at the rear of the torsion bars. I've found these to cause thumping/rattling noises even when they "look" ok. They get worn and allow up and down movement of the torsion bars. Use a prybar to check for any small amount of movement. Let us know what you find, good luck!

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The 07 and up had struts on the front, 2006 is the last year for torsion bars on the 1500's trucks, tahoes and suburbans .

I had a weird noise like that with my older Tahoe, it turned out to be a loose bolt from the transmission mount to the transmission. It didn't appear loose, till one day I was just tightening up every bolt I could see and found it that way

 

[mtl111]

The 07 and up had struts on the front, 2006 is the last year for torsion bars on the 1500's trucks, tahoes and suburbans .

I had a weird noise like that with my older Tahoe, it turned out to be a loose bolt from the transmission mount to the transmission. It didn't appear loose, till one day I was just tightening up every bolt I could see and found it that way

My mistake, there was no year of the vehicle mentioned in the first post and i didn't notice this was in the 07 and up forum. I normally only get notifications for the OBS trucks.

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