my new 2500 has just under 9k on it and I've put about 4 gallon in it so far and it's down to a 1/4 tank of def now and I just purchased 2 new jugs of fluid today. I haven't had any issues. I do let mine run down usually to around 1/2 before I top it off. I have read someplace that it's mostly water.
If you ever get stuck somewhere and run low, distilled water will get you on your way.
I won't own a diesel anything built after Oct 2003, and my preference is pre 1998. 1998 is when the low NOx software started and EGR started Oct 2003.
Kevin
