Humming noise when idling 3.0L Duramax

TimelordLink

TimelordLink

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I've got a 24' ZR2 bison with the 3.0L Duramax and it makes this strange humming noise while idling. I've got about 3500 miles on it. Is this a normal noise for a deisel (first deisel) or do I need to take this to the dealer?

Video of Noise
Longer video
 
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It sounds like this, if you read this thread and follow the link to the Duramax Forum you should get some ideas. It isn't an issue no matter how you slice it.

Interesting noise coming from under truck....

So I've had this noise since shortly getting my truck. It's been to the dealer and of course they can't "Recreate customer complaint". So hopefully someone here can point me in the right direction to resolving it. After the first visit to the dealer the noise seemed to be less frequent and a lot...
www.chevyzr2.com www.chevyzr2.com
 
HighTechPauper said:
It sounds like this, if you read this thread and follow the link to the Duramax Forum you should get some ideas. It isn't an issue no matter how you slice it.

Interesting noise coming from under truck....

So I've had this noise since shortly getting my truck. It's been to the dealer and of course they can't "Recreate customer complaint". So hopefully someone here can point me in the right direction to resolving it. After the first visit to the dealer the noise seemed to be less frequent and a lot...
www.chevyzr2.com www.chevyzr2.com
Click to expand...
I have read similar in other threads most people can't find the noise and the dealer says it's no big deal or can't replicate.

When I recorder that video it was after the truck had been running for 40 minutes around town in 100° heat... About 2 hours later I ran down to the store a couple miles from the house, windows down trying to listen for it. And it didn't make it when I started it drove stopped anything... When I got back to the house I heard it briefly. As I parked. Sat there for a few minutes but didn't hear it again.

It's just such an awful and loud noise though.
 
1000037495.jpg
 
Is it coming from the transmission or motor?

Sounds like a bad throw out bearing in a manual transmission. But I'm guessing you don't have a manual transmission.
 
AXE said:
Is it coming from the transmission or motor?

Sounds like a bad throw out bearing in a manual transmission. But I'm guessing you don't have a manual transmission.
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Correct it's an auto.

It's hard to pin point where it's coming from... It sounds more like it is coming from the exhaust.

I can't hear it in the cab. I can only hear it when the truck is running and I'm not in it but it doesn't do it unless it's been driven a bit.
 
TimelordLink said:
Correct it's an auto.

It's hard to pin point where it's coming from... It sounds more like it is coming from the exhaust.

I can't hear it in the cab. I can only hear it when the truck is running and I'm not in it but it doesn't do it unless it's been driven a bit.
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Check the heat shielding on the exhaust. Some people have reported them being up against the drive shaft. Also make sure it's not touching the body where it can vibrate.
 
I kid guys. 6.2 or 3.0, this has to be one of the most helpful Forums out there. A lot of members actually try to help out and if they can't, they will point you in the right direction.

Granted there are a few members that suffer from baby huevos syndrome and can't take a joke because their man hood is at stake, but other than those few sprinkles the Ice-cream as a whole is really good.
 
Maybe its the lifters? :sneaky:
Honestly the heatshield sounds right. I have also heard bolts make a similar noise when they are barely loose. A high frequency pitch like that. I think we have all seen bolts on these trucks which have not been torqued down properly from the factory. Check the ground strap on your 3.0 while you are at it. Make sure its not loose:)
 
Alright y'all I got up under there for awhile today after I ran some errands and found where it is coming from.

@HighTechPauper 's link that linked something else was correct. It is coming from this module on the exhaust right before the muffler.

Based on the threads I read on other forums this module just makes that sound for awhile but I will go away after around 8-12k miles.

Now I need to figure out what this module does out of my own curiousity.
 

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@TimelordLink, I am guessing here, but based on the description of the junk that came out of the mounting location when he removed it to have a closer look, I am guessing the reason it quiets down after some miles is that if finally gets packed with crap, I will be removing mine occasionally to clean things up a bit to try and keep the soot and whatever the metal debris was from building up. IMHO/YMMV
 
@HighTechPauper, I think cleaning it out periodically is a pretty good idea as well.... Maybe Everytime I change the oil.

If you figure it out first though I expect a report as well.... My initial guess is it is something do with emissions.
 
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