Cool video.
I was curious too so I did a quick Google search on the matter. PLEASE take it for what its worth, "I read it on the internet, so it gotta be true". Im definitely no expert.
It looks like GM and Isuzu teamed up in 1998 to build the Dmax. It wasnt until 2000 the first Dmax was sold in a GM truck. I found that info here. http://www.dieselpowermag.com/features/1303dp_history_of_the_duramax_diesel_engine/
Dodge and Cummins contracted in 1989 to put diesels in their trucks. found here. http://www.allpar.com/mopar/cummins-diesel.html
So depending on how you look at it 9-11 years.
So it does appear that Dmaxs are produced much faster to supply the demand of REPLACEMENT engines.
