Does anyone know how many 2003-Early 04s came with a NV5600. And of those how many were 4x4s?
Ha... I’m having a hard time hunting one down.

 

Tons! Dodge sold and sells a ton of Dodge Cummins trucks every year. As do Ford and GM. Even my 3rd Gen 2wd Cummins with an NV5600 is not rare at all.

Not sure why you would want an old 2003-04 Dodge Cummins. The 2003 Dodge Cummins was the 1st year of the 3rd Gens and had numerous issues and few benefits.
Primarily the early 2003 3rd gen Cummins would drop valves and valve seats. The Cummins head was redesigned for 2004.5+ engines. Plus all the HVAC issues in the early trucks.
Plus the really crude ECM. Plus the NV5600 is long out of production.

If you are shopping for a used Dodge Cummins, there is no perfect year. Buy the newest, lowest mileage, non-modified, non-rusty, non-farm, non-work one you can find.
The 2006 Dodge Cummins were likely the worst 3rd Gens, 1st year of Canbus, but all those electrical problems on those old trucks have likely been fixed by previous owners.
Plus the short geared G56 OD gear on the 2005-07 5.9L trucks, corrected in 2007.5 when the 6.7L came out.


I own a 3rd Gen, but if I was used truck shopping, I would be looking at the 4th Gens and rule out the 3rd Gens. Unless you have emissions testing in your area.

IMO, a G56 4th Gen, with few options, (no LCD display in the dash, no sunroof, etc), deleted 6.7L, is a great truck with minimal factory issues.

 

My opinion is there is no perfect year for the gen3 cummins. But I will take a 5.9 any day over the 6.7. The first one to two years of the 6.7 were full of reliability issues. From particutate filter problems to driveabiliy problems and poor fuel mileage plus the towing specs were not that much better than the 5.9. Only the last three years or so have seen a significant increase in reliability and increase in towing specs. The NV5600 was a good option and most people liked it.