Just look at the body styles of the trucks.

Pre-93, 1st gen

94 - 01, 2nd gen

02 - Current, 3rd gen

 

in 98 they went from mechanical engines to electronic engines. Then in 02 they went from injection pumps to high pressure common rail. As far as which engine is best, it's a toss up. Each have their own strong points and drawbacks.

 

alright so if i have a 2002 (the 2500 series), which they used the 2nd gen body style, not the new body style, the engine they used was the common rail system, and not injectoin pump ? im confused. i traded in a 2002 1500 the first year of the new body style, it had the 20" wheels sport package, and i traded it in on my 2002 ctd with the older body style. so from what you just said the engine inside my truck is different from the 2001 engine >? im curious to know im not to much into the technical on this, i am a diesel mechanic, just not familiar with cummins and personal vehicles. i work on Mack's