My 2012 2500 Hemi has been making a hissing type sound, which sounds like an exhaust leak, since I bought it new. It only happens when you step on the throttle, don't really hear it at idle. I had the dealer I work for look at it and the tech said it may just be the belt that's not worn in yet. I have about 5,300 miles on it and no change. I even had a salesman tell me that sound is normal on the 2500 Hemi. There are no lights coming on and the engine seems to perform fine. Anyone have this and know if it's normal? I haven't had a chance to listen to another truck so hopefully someone here can answer my question. Thanks.