Early 04 or an 04.5 5.9 Cummins Dodge Ram: How to tell

Not sure if you have an early 2004 or a 2004.5? Find out below:

This question comes up frequently on forums and social media groups.  I have not found VIN numbers to be a reliable method of determining whether you have an ealy 04 or an 04.5 Dodge Ram with the 5.9 Cummins.

The method I have found that so far is 100% accurate is pretty simple: The horsepower rating.  This can be found on the long white valve cover sticker (drivers side):

The Bottom Line:

If your engine is a 325HP engine like the one circled above; it is a 2004.5 truck

If your engine is 305 or lower; you have an early 2004 truck.

-If the decal is gone, you can check your turbo wastegate.  If you have an electronic wastegate that is connected to the engine wiring harness; you have an 04.5 truck.  If you have a mechanical wastegate with no electrical connector, you have an early 04 truck.

What difference does it make:

Injectors: This is a major difference when buying injectors.  Early 04 trucks use a wide spray pattern injector nozzle and piston bowl.  04.5-07 trucks use a narrow spray pattern injector and piston bowl.

Generally you need to match this to your truck exactly, but there are cases where you can use the early model injectors on late model trucks; however this does not apply in reverse!  Late model injectors should never be used on early 04 applications unless the pistons have been changed to a narrow spray pattern design bowl.

Checkout my line of BBI Injectors here, I offer discounts on tuning packages when you bundle a set of injectors with your tuning package:

BBI Injectors from 5-9 Diesel

On the fly tuning:  The MM3 tuning platform is what I support for tuning 04 and 04.5 trucks.  04 and 04.5 years are the cut-off between standard tuning and on the fly capable tuning.  An 04 cannot do on the fly tuning, but an 04.5 can👍

-If you are adventurous, you can switch your early 04 ECM with one from an 04.5 or an 05 year 5.9 Cummins truck (CM848D and CM848E respectively).  This would enable your early 04 to have on the fly tuning but will require custom tuning to achieve. Get in touch for more details on this swap.

Looking for custom tuning for your 04 or 04.5 5.9 Cummins: Click below:

Custom Tuning Products


See my tuning in action…

High Altitude 12 Valve Tune Cold Start

An early version of my towing tune…