Anyone else getting a chirp under their hood? I notice it does it between 1700-2300 RPM's then it goes away. It sounds like it's turbo related, just want to see what everyone else thinks.

I notice a chirp also. It will do it between 25 & 30 mph when I give it a little throttle quickly. Also, it a parking lot- when the truck is rolling, a little quick throttle will cause it. Turbo related??

probably turbo bark.. search for the term, plenty of info on it.

No turbo bark, u all need to go to a truck pull and hear what turbo bark is.

Idler arm pulleys most likely. My truck was built in February 2004 and I had the same thing. First they replaced the belt but it returned the next day. Next they replaced the pulleys and it was gone for two months. My truck was having other issues not related to this but the GM/Duramax Quality Manager who was working with me to fix the truck noticed this in the vehicle service history. He sent a new power steering bracket to the dealer to install because he said they had some that were not machined correctly get out and it was causing premature failure of the bearings in the pulleys. Since Ozzy's is an 05' I doubt this is what he's seeing but for those of you with early LLY's it worth looking into.

Birds trying to escape. :D

Took my 02 in to the dealer for making that chirp noise... They found the alternater was worn down, and the belt had some cracks in it.... replaced both, no more chirp.

Had a chirp or squeak coming and going . water pump bearing was bad. drop the belt and see if it is there , thats how we found mine

Hey ozzy we have seen 2 05 llys with the chirp and it was the pulleys with a issue.

I've got the chirp on cold startup, but at 1500-2000 RPM, I'm rolling and can't hear it. I assume that I have the bad pulley bracket and will have the dealer look at it when I get the oil changed. It's a bit of a PITA since I have to leave the truck overnight so they can cold start it.

I had a chirp that lasted for 15 to 20 minutes every morning. It seemed to go away after engine temp reached 210. Took it to the dealer; replaced belt and tension pulley. No more chirp.