2500 owners, I have the same problem. Not 1000 miles on this truck and its horrible on startup. Foolishly traded my 150 for this! I took it to a dealer in Colorado and they told me "I know its not what you want to hear, but its normal". No analysis, no info from where the noise comes from, nothing and no resolution. Obviously, its not normal. Something has not been designed correctly or a bad part etc... If exhaust, so be it, what is the fix? Thanks, Veno