During this time period, the DD15 has only required one oil change at the 75,000-mile mark. The dipstick level has remained at the full mark and therefor the Detroit DD15 has required no additional oil to be added. 75,000 miles seems like a long time between oil change intervals, however, this is the factory recommended mileage for the DD15 filled with FA4 type oil and a fuel mileage average of 7 MPG. Unfortunately, FA4 type oils are not widely available at this point in the field. For that reason, I am back to 50,000-mile oil change intervals due to the fact that my crank case was refilled with CK4 designated oil.
The task of adjusting the valves which most people call running the engines overhead was performed early at around 92,000 miles because of scheduling around freight demands, instead of the factory recommended 100,000 miles. There does not appear to be any change in the trucks performance since the overhead was run. The fuel filters, oil filter, and cabin air filter have been changed once. Other than normal chassis lubrication and one wheel alignment after the truck settled in New Blue has diligently performed flawlessly up to this point.
The worst fuel mileage was an 8.698 involving a 43,000-lb. load in the mountains and my best one leg trip from Statesville to Atlanta being 13.4 with an 18,000-lb. load. The lifetime fuel mileage is 10.075 and the lifetime diesel exhaust fluid (DEF)consumption rate has been 267.87 MPG.
Keep in mind all these results were obtained while pulling my 2008 Utility dry van trailer with aerodynamics. My trailer has aerodynamic aids from Nose Cone, Fleet Engineer Side Skirts, Stemco Trailer Tail, Flow Below wheel covers, and the truck and trailer shod in the latest fuel-efficient X1 wide-base single tires from Michelin.
At this point, it would be easy to say I am more than pleased with the performance of my 2018 Cascadia AeroX.