With 15k on my truck now and towing often but only with around 5k on the trailer I would say my engine is starting to break in! I can now pull small mountains loaded in 6th gear. **** this thing is getting even more powerfull. I am very impressed as to how the power keeps increasing.

 

Saw: Mine has 15k on it and I also pull a car trailer @ about 5k... I am also impressed, the more I drive this truck the more I love it...

 

Great news! Hopefully the mileage will also increase with torque!