I just traded in my 03 auto for an 04 6spd manual. I've been transporting RV's from the east coast to the west coast and really wanted the 6spd, so I could install the exhaust brake. And have peace of mind. The date of manufacture: 6-04. What's the difference? Michael.

 

Mine was built 6/04 also so it is an 04.5. If you look at the sticker on the left side of the engine you should see ISB 325 which is the 325hp 600 ft/lb torque engine. The early 04's had the 305/555 engine.

 

Any truck assembled after 01/01/04 is a 04.5 "600". Congtrats on the new truck. Make sure you get the new flash. TSB 18-037-04
Odie