Duneslider, we share some similar results. I tow a 27' 9000#GVW travel trailer that weighs about 8200# on the scale including the tongue weight. My comparison was between an '02 Expy Eddy Bauer, 5.4l 2 valve Triton and 4spd in front of a 3.73ls and a '18 Expy Platinum Max, 3.6l EcoBoost and 10spd in front of a 3.37ls. Both have the HD Towing Package available at the time of manufacture. Neither has had any modifications other than a bug deflector on the front edge of the hood. I am retired and in no big hurry and while towing, I generally stay within 60-65mpg when traffic permits or I speed up if necessary while trying to maintain a safe stopping distance. Except for areas where the tranny would unnecessarily shift frequently, I generally use the cruise control for open highway.
For this apples to apples comparison, we towed this trailer from Texas to Alaska and back over the course of 4 months traveling north along the East Slope of the Rockies and back along the west coast and across Arizona and New Mexico. The distance was roughly 14,000 miles and about 10% of that was solo sightseeing adventures and 90% was towing on everything from flat and level interstates to day long stretches of barely 2-lane gravel with many grades mixed in on both types of roads. While the Platinum came with a slightly boosted version of the 3.6l that reportedly produces about 25 more hp on 91 octane vs 87, I stuck with 87 for these trips.
In 2014 we were obviously pulling with the '02 Expy. Overall fuel economy was 9.2mpg and necessary downshifts often bumped the tach to over 3500rpm. On extended grades like Raton Pass, I prefer to shift it to 2nd and drop in line behind the big trucks and climb at half throttle. Downhills on those type grades were also taken in 2nd with occasional light taps on the brakes to limit speed from the heavy trailer pushing us downhill. As be bought this Expy new in '01, none of this was new to us.
Last year we repeated this trip with the '18 Expy. Overall fuel economy was 11.9mpg, a bit over 20% improvement! As you noted, the tach rarely exceeded 2500rpm, but on a few 6% or greater pulls it did get up to about 2800rpm. This model also has Tow/Haul mode that I used. Also as you noted, it was always in the right gear, both up and down hill. What I was not anticipating was that if the cruise was set and going down hill, it not only downshifted to maintain the set speed, but activated the brakes if necessary. I first realized this by the reflection of the brake lights on the front of the trailer. There were times on rolling terrain that I would have preferred it to gather a bit of speed on the downhill and I'm sure those who were behind me wondered WTH I was doing. When I got into those situations, I switched off the cruise. Amazingly, the Expy sensed the downhill and did downshift, but I'm pretty sure it wasn't activating the brakes as it did with the cruise on.
In summary, the new Expy got exceptionally better overall MPG. It was much less tiring to drive. The interior ride was far smoother and quieter. The fake engine sound is pleasant to me, but seems corny, although it does sound like they tie the sound to the rpm and engine shifts and this sound seems slightly different depending on driving mode.
Wishes: Since Ford advertises this a great tow vehicle, they should offer extendable tow mirrors. I also wish the mode selector would remember the last used position.
