I'm not certain if there is a doughnut between the exhaust manifold and the exhaust on 2005 models, but the first thing I would do is if the sound is loud, let the truck cool off. Then start it up when the sound is loudest. Get under the truck and place your hand near the connection. You will definitely feel the exhaust leaking if that's where it is coming from.
Also, check the for a loose connection there, and tighten if needed.
Also, check the for a loose connection there, and tighten if needed.