Rattling / Resonance from RR under light throttle

[SnowDrifter]

Took me a bit to realize this was coming from the hoe and not the construction site

Sound comes from RR area from the perspective of the drivers seat. Seems to be worse when cold, between non existant and barely noticeable when not (30+min drive time).

Happens at a very specific RPM ~1300, light throttle. Going slower or faster seems to alleviate the issue.

Checked catalytic converter trims, fuel trims, Neither of those show any issue w/ the cats or signs of obstruction. Noted no sound when struck with a hammer.

Checked heat shields were tight and not contacting.

Would I be correct in my takeaway that this is something internal with a muffler?

Little video. Apologies for the music in the background. This was a 'oh hey there's that noise' instead of a diagnostic drive

 

[drakon543]

try to get another video with any background noise you can eliminate. i cant hear anything particular that i can pinpoint as something that isnt background noise. as a side note with the truck parked and nothing is contacting might not be the case under load. as the exhaust is bolted straight to the engine as the engine flexes a bit under throttle can pull the exhaust closer to something. so on that note do you have any spots on the exhaust that are close to something but dont appear to be touching while it parked. they could be touching when your accelerating. other diagnostic options tp check to loose heat shields and spots where it could be touching. while the exhaust is cold you can stuff a shop rag under some heat shields and do a short jaunt around the block. dont go far as you dont want to get the exhaust too hot with those rags in there but it will add some cushion as a test.

 

[afpj]

Sounds like a buzzing noise right after you completed the turn, like an air compressor? Unless that was part of the song.

 

[SnowDrifter]

Sounds like a buzzing noise right after you completed the turn, like an air compressor? Unless that was part of the song.

Not part of the song. That's the noise

 

[iamdub]

Only does it under load? U-joints? Transmission? Rear end?

 

[Doubeleive]

get under it with a rubber mallet and start smacking stuff you might find it that way, that's how I found a loose heatshield on a cat, had the muffler shop tack it down, noise gone another one was a loose heatshield on the transmission, that one would only resonate at a certain rpm also.

 

[S33k3r]

Do you have an air ride suspension?

 

[SnowDrifter]

Yeesh..... Well it's definitely inside the muffler whatever it is.

Anyone make bolt-on replacements?

 

[iamdub]

Yeesh..... Well it's definitely inside the muffler whatever it is.

Anyone make bolt-on replacements?

That's much better than anything else it could've been.

They're ALL bolt-on with these!

 

[PNWYukon]

If you have the original muffler, check the heat shield on top of if. Mine made similar noise because the shield was torn from welds at both ends.