a really good place to look up info is TDR.com, the best place to get info, i loved my 04 2500 till my dad took it because he needed a truck ( i would have to kill him to get it back now) so i just ordered a 11 3500,can't wait till it comes in (just got my vin). there was an 04 and a 04.5, some minor fueling differences and horsepower ratings. The automatic is fine for a truck that isn't a true work truck. i put a aftermarket pan on the 04 with a temp guage in the srt gauge pod/ handle and watched it. and of course the srt hood.