Been browsing around on auctions and marketplace, why do some 2011-2012 Cummins have def when def didn’t come out till the new and improved 2013 updated 4th gen’s? Really confuses me. I have seen 3 2011-2012 4500s and 5500s with def. Makes no sense to me and haven’t found a thread on it. My coworker has a 2012 5500 and it has def, appears to be a similar but not identical doc,dpf, and def dosing system as a 2013+. What’s the deal, is it a retrofit system? Seems every one I see is a cab and chassis only, no pickup versions 2011-2012s have I seen with def, ever. Unless I’m missing some thing about cab and chassis emissions standards and am a complete idiot, but almost every 4500-5500 ram cab and chassis seems to have def in this area, here in the treasure valley Idaho area. And yes, I have crawled under them and looked at everything, definitely all factory components and no aftermarket or California retrofit systems. Curious if someone knows something I don’t. Picture is of a 2011 5500, as seen, has a def filler cap. Thanks

2011 5500, with def?! What’s the deal

 

It may have been required on the heavier duty trucks......