I have an 09 2500 Hemi, at higher speeds it has a kind of tick or knock depending on your ear. If you step on the brake it goes away and it doesnt do it at low speeds or idling. I had the dealer drive it, they say its road noise. Im a lady, not a moron. I know its there and not road noise. I pushed on the idler pulley and it has just a small amount of wiggle, I would have thought that if it was the pulley it would do it at any speed.
I also had a whine, but think I found a solution on another forum.
Hope this is the right forum, the 4th geners say an 09 2500 is a 3rd generation.

 

Generation makes no difference. If that is the only answer they gave..shame on them.
Idler pulleys are checked with the belt off. If they free spin, they are bad. If they stop right away they are good.
Tensioner pulleys do have some side-side play depending on how you move them.

The noise could be an exhaust manifold gasket leak, manifold metal expansion, EGR valve clicking away or Engine knock(ping)
I actually have a similar ticking noise at higher speeds as well(40mph+). It's hard to describe and is NOT rythmic to the engine. Almost sounds like metal crackling when its cooling. I do not have pinging issue's as I run 93oct. I have however, installed aftermarket headers re-using the stock exhaust manifold gaskets. I do not see any carbon spewing out of the bolt holes or anywhere so that is the extent of my diagnosing of that noise.
It was never anything that bothered me enough to jump into and diagnose full on. To me, it's a 'normal' Ram sound that will just never go away. I have 12kmi on my truck right now.
I think that many others probably have it and just havent noticed it. I have noticed several noises that others say dont exist until I show them exactly what to look for.
One noise is the odometer stepper motors making a zip or ratcheting sound when you open the door after 60sec or so. It's there, but faint.