Air ducts make loud banging noise?

Hopefully, you're still under warranty. It's probably the set of plastic gears that operate the heater doors. Often times a tooth breaks off causing this symptom. A reasonably easy fix, just a pita. Hope that helps.

Blend doors have failed.

I know you have the 426 but that shouldnt effect your warranty on the other parts that aren't the powertrain. Hopefully the dealership isn't a biatch about it. But they might be because the dash has to come out for that repair and the labor is killer. The part needed tot fix the actual problem isn't that costly but like I said the labor is what kills you.

GL!

Thanks guys. I have an extended warnty. The dealer I am using is good with aftermarket parts. They know I had the 426 installed and fix things. In fact they all said it was a great job. They are use to aftermarket builds as they are the main shop for the viper club, and I have a standing order that only Scott works on my truck, he is the lead master text for the vipers.
Well if they take off the dash then maybe they can find this annoying chirp that drives me crazy from the dash too lol. Thanks again for the help

Gremlins?

Had the exact same problem in mine a while back. Was waiting for a good day to take it in for service. BUT, in about a week to 10 days, the issue (sounded like a door slamming) went away on its own and never returned in about a year now.

Hmm can I be so lucky? My appointment not tll after holidays so well see

Blend door acuator, I see quite a bit of that.