Noise around 1200-1400 RPM, Buzzing sound.

[ls1dmax]

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Hello
I ended up getting a 06 LBZ with 71k over the weekend. Really like the truck, but I found an issue already.
Truck was parked all day untill about 6PM when I used it, turned off the radio and rolled down the windows just wanted to hear the engine. I noticed when accelerating that it would make a noise, I want to say like a buzzing noise. Well I noticed it was doing this noise through a certain RPM when accelerating and through shifts as it got to a certain RPM. I watched the gauge and the noise is made between 1200-1400 RPM, I think it does it at exactly 1300 RPM. I was just driving in town, when I drove through a parking lot I could hear the noise loudly or just driving around town if the RPM got around 1300 it would make the noise in any gear. And when it shifts from 3rd into 4th the RPM drops around 1300 so the noise is constant unless I accerlate or let off to avoid the noise.
I did a search and best info I could find is that some people mentiond checking the oil level, and thought maybe the exhaust could be cracked.
Sorry for the long story just trying to be a specfic as possilbe, sorry if it's newbie question too... I know someone's going to say it's just the turbo doing it's thing, lol but no it's the turbo noise.

Thanks in advance

 

[83GMCK2500]

You checked the fluid in the rear diff? They notoriously came low on oil from the factory. After driving around and making the noise for a while, get out, crawl under there and start carefully touching things, the differentials and transfer case shouldn't be hot to the touch. The transmission will be warm from working and will transfer some heat to the t-case but not a lot. See if anything is getting hot.

 

[t2ch]

Does it sound like a vibration? or different.

I have a CAI and mine was loose. It vibrated somewhere around 1200 RPM. Drove me crazy. snugged it down and all was well.

Mine was loose where it bolted to the truck.

 

[samfraser]

heat shields, there are a few of them, harmonic vibrations will cause these to vibrate at different resonant frequencies, very common on all dmax's.

 

[stacks04]

x2 on the heat sheilds, will it do it in neutral if you rev it, or can you make it do it while standing on the brake and gas at the same time i.e. power braking it to 1300?

 

[mgiroux236]

I have a similar noise/vibration that happens around 1300-1400 RPM.... Is driving me crazy too... Though it was around the exhaust manifold, where the exhaust pipe connects to the manifold... Have spent weeks under the truck with no luck... I can only get it to be there when moving... Can't seem to make it happen at a stand still....


2007 Sierra 2500HD, 4 X 4, Durmax 6.6 L