2004 Crew cab exhaust system noise?

I'm new to the site and my 04 Silverado's exhaust makes a "tinging" noise while cooling. Not your normal popping noise which is normal for all vehicles. I mean like someone is under there with a little ball-ping hammer hitting randomly for up to an hour after shutting it down. I haven't had it in to be checked out yet. Only 3000 miles and it's done it since new. Any help appreciated. It's a pain for me to get to the dealer so I wanted to get a little feedback before I talk to them. Thanks.

My '04 1500 does the same thing..... I would like to hear any feedback as well.

I've had the 'ballpeen hammer noise' on every other vehicle I've ever owned. Its simply the exhaust cooling.

I hate to say it, but I've had a '92 1500 and '98 1500 and never had a problem....

I have a 2000 silverado which i just recently had true duals put onto and it makes the same noises you described, and as someone else mentioned it is just the exhaust cooling down, most likely the mufflers. One thing i would like to add , when i had the duals installed ,(left original cats alone as well as the o2 sensors) I lost power for about the first month or so. Not sure why and the muffler shop took off the dynomax mufflers and installed flo pro's (love the sound now :D) My guessing is that it is too much of a change for the computer to make from a single restricting factory exhaust to such a free flowing dual system. Any thoughts on that one ?