Ram used an alternative method of nox emission control (a lean nox trap) on the 2500/3500 pickup trucks until 2013, when they added the DEF system.

The flatbed 4500/5500 Rams got DEF a little earlier, I think it was 2011 but am not positive.

'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118