14 to 18 is my favorite era of the Ram CTD. I’ve put on a couple NoX sensors, but certainly not a common issue. Maybe replaced 2 def tanks due to 1 contaminated and the other the DEF quality sensor (part of tank). I own a 17 and the few times we’ve driven it absolutely love it. I actually had myself convinced to go with a 6.4 Hemi but about a year ago a 3500 long bed single CTD came in to the dealer I work at and I made it mine. It had 17k miles on it. We’ve only put 6800 miles on it this year….. what a waste