This is my third LS and the last one I had did the exact same thing. Its so annoying but could never figure out what it was. Maybe you guys can point me in the right direction. I will try to describe the circumstances of the noise.

I have 20” wheels on 35 series tires so road noise is louder as to be expected. When going over certain types of (hollow or raised?) concrete pavement, there is a “keys rattling in a tin can” buzzing noise that seems like its coming from the steering column or below the car. Its fairly faint and only happens when the resonance from the tires is just right and I am barely pushing on the gas.

Would really love to solve this “issue”. Lol.

 

Does this happen when you hit bumps, and when you apply the brakes lightly, for the first time? A metallic sound, as if you hit a piece of metal with a rubber mallet, just right?

If so, my indie told me to install the original shims that are missing from the car. He drove my car very carefully, then inspected it on the lift. He even tapped the top of my brake pads with a small hammer to duplicate the sound. I do have the shims but I have not replaced the brakes so I don't want to put them in until that time, so I live with it....this forum also states what my indie said on old threads...it's worth a shot.

If your shims are there, then obviously it wouldn't be the issue....

 

 

The aluminum heat shields under the chassis can create your tin-car rattling noise. There are several of these heat shields that are strategically placed between the exhaust system and the underside of the cabin. One or more of the mounting bolts/screws may be broken or loose.

 

I have the exact same sound. To me it seems to be coming from the passenger side. From what people were describing the sounds of their bad LCA caster bushings I was hoping the bushings I plan on replacing would help. Aluminum heat shield does sound like it'd make sense though

 

It could be an idler as well-I would check the heat shields first, for sure!