Group_er

Ok guys, finally finally had the time and availability to take the truck into the dealer. they replaced the fan clutch, and the noise has been gone since. (2-3 weeks) here’s a copy of the service order from my dealer. Hopefully it can help some others out:

Just an update here, dealer replaced the alternator, which didn't fix the problem. Now they think it's something internal to the engine, They ordered some internal engine clutch related parts? which have come in, Ive just been too busy to get the truck back in to the dealer. I will post an update once I do..

Got the truck into the dealer yesterday, They thought the noise was coming from the alternator, after 5 minutes of it idling and making the noise the tech put his hand on the alt and said it was too hot to touch. They're going to order and install a new alternator next week. Ill keep the forum posted on the results.

Yes its very annoying. I can hear it when driving slow, coming to stops, driving around town sort of thing, but it can't be heard at highway speeds.

Ive tried uploading the video to YouTube, Lets see if this works:

Trying to troubleshoot an annoying Horn like noise coming from the front of the truck upon cold starts. It goes away after around 30 Minutes of driving. The sound comes and goes and almost varies in pitch up and down. But then some times will stay consistent. I haven't been able to tie it to rpms, steering, engine load, braking, or anything like that. Only possible clue is it goes away after the truck is warmed up. I have a good video of the truck at a cold start where you can clearly hear this noise. Anybody have any ideas what could be causing this? Can anybody tell me how to post this video on here? -unfortunately, there videos 4K, and fairly large.. Thanks for any help guys, This noise is driving me nuts! '22 GMC 3500 Duramax