Lets also note Jake, you only tow with your truck...
IDK I use full synthetic and the truck shows 10K when it says its time to change the oil. I had a sample sent out of the first oil change and the company said it was fine, it could actually go more.
Ford says its a 10K oil change. Claudia VW TDI is the same, VW oil costs 70 a gallon and its rated for 10K.
I'll snap a Pic of my computer readings today..