X3 I have to agree with what Redwoodcamper said , not trying to change this into a diesel vrs gas thread. But I have had 3 gas tow rigs over the years, and 1 was a Ford V10. Getting over hills with a bit of a grade will mean some downshifting and trans working up and down gears. Using a cruise control in those area just seemed like a way to to beat way to hard on your transmission. The 6.7 I am running now with a mild towing tune will go over most hills on cruise running 65-70 mph and never shift out of 6th gear. Not saying it will do that in real mountainous terrain, but in hilly terrain no down shifting at all.
