Originally Posted by Bmwister
After break in and after the first oil change is my advice. In my case, that would be ~1500 miles.
I was going to say about the same thing
Though I may go 2000 miles before I do the oil change...... Regardless, if you are going to tow something that heavy for any extended time don't wait on the 8000 mile first service to change your oil, do it before you hook up the trailer and consider synthetic if for nothing more than it's high temperature stability.