165,000 on my 2012 one ton dually LTZ. No deletes, fully stock since new, except added a Wherli FPR screen. Have replaced DEF tank (heater failure) under warranty, and two glow plugs. Running Rotella synthetic engine oil and Diesel Kleen lubricity enhancer. 90% of miles are highway, often towing 5th wheel or carrying truck camper. Am monitoring engine oil and transmission fluid via Blackstone Labs.