Tune. Tune. Tune. Some people remove shutters, if they are on your truck. My recent trip to Montana saw Boseman Pass at 35K rpms, 3rd gear, flat on the floor, down power rated temps, pull over at top of grade, with every other tow vehicle to let cool down. Did I mention Tune? Some people install external oil cooler with external filter, I did but I am not satisfied with oil temp. Tune.Pull a 5000 lbs travel trailer and see a temp rise on all gauges when going over uphill mountain grades
RPMs at 28 to 3200 Long grade will see a rise of 15 to 25 degrees and close to limp mode
Any recommendations???