I have a F350 4x4 long box diesel. I always used tow haul when I towed our fifth wheel. We have now downsized to a tow behind TT. The friends we camp with have TT and they never use tow haul because they get worse mileage when they use tow haul. One has a F150 v6 and the other has a Ram 1500 with hemi. What is the story with tow haul mode and travel trailers? All 3 travel trailers are 19 ft and around 6500lbs.
Tow/Haul mode is exactly what the name applies. It changes the shift patterns to allow for easier towing, both on the driver and the equipment. In most models it also allows for a type of engine braking for descents. I guess on the flats you could turn it off, but any time I towed our FW or when we had a gas MH and towed a car, I always used the tow/haul mode. That's what it was designed for, and I imagine there is a risk to prematurely aging or even damaging the engine or transmission if you towed without it. I don't see how a TT would be any different. It does use more fuel. How much is debatable. I have never purchased any RV with mileage as a consideration otherwise I'd have bought a condo and a prius.
My 2015 diesel 2500HD Silverado locks out the highest (6th) gear when in tow/haul mode. I could get about 1 to 1.5 mpg more if I didn't use tow/haul, but I side with those of the opinion that it is easier on the transmission if I use tow/haul.
Interesting, our 2008 F250 with 5 speed is happy to go into 5th with tow/haul on so long as it's flat ground (climbing it will drop gears as needed). Doing a little search on the internet, it seems all over the place in terms if transmissions lock out the top gear in tow/haul.
City driving there might be a small difference in mpg as it holds lower gears longer to improve performance. Once on the freeway and up to speed and locked into top gear, it won't make any difference. I typically avoid city driving and have never noticed a difference in mpg.
Where it really makes a difference is in the mountains. Avoids hunting for gears which can be hard on the transmission and will help downshifting on downhills for a more comfortable and safer drive. You could leave it off and manually force shifts but why?
One of the guys had to replace the transmission on his F150 he blamed the mountains. I bet he was not using tow haul while driving in the mountains.
That tells us nothing. We don't know if he was using tow/haul or not, we don't know what he was towing, we don't know how bad the grades were, we don't know if he maintained the truck, etc....
I believe it increases line pressure which will help your transmission live longer. Especially if it is shifting a lot.
in my f350 towhaul mode changrs your shift algarithims so when accellerating it lets you go a little higher in the rpm before shifting to the next gear, it also holds the gear a little longer before downshifting. I tow a 13000lbs 5th wheel the only time I use it is on the bigger passes in the mountians and then only rarely.
Maybe it was what he was pulling that did it.
I ALWAYS use tow/haul with my 2020 F-350. when towing... That's what it is for, hence the name......
Using Tow/Haul is not going to affect fuel economy while towing and you are definitely not going to go wrong using it for all your towing. However, with a new F350 diesel towing a lighter tag trailer, something under 8k lbs, tow haul is hardly needed. If you find it more comfortable to tow light trailers set to "normal" I'd recommend using "normal" for towing. Activating the Exhaust brake affects the shift points to some degree as well. Sometimes with a light trailers I'll use "normal" and no exhaust brake, sometimes "normal" plus EB. With a heavy trailer I usually use Tow/Haul with the EB set to "auto". If just driving on flat ground at slow speeds I will sometimes set the truck to normal no EB even with a moderately heavy trailer, (I consider my fiver a moderately heavy trailer at about 16000 lbs).
I did a test last weekend. Heading to the camp ground tow haul on 11.6 mpg
Heading home tow haul off 10.4 mpg. I could definitely hear and feel the transmission shifting a lot more.
So many factors come into play with MPG which is why most RVers never even bother. Terrain, weight, wind, traffic, speed, etc. Some fella at a gas station once asked me what kind of mileage I got on my class A. I said; it gets great mileage for an apartment.
I wouldn't say RVers never bother, I know very few that don't track their milage. for me I realize it is going to varry but not by much it is in a general range and if it goes out of that range for no aparent reason I know to start looking for somthing wrong like a wheel berring or what not. plus I am always looking for ways to improve milage.
What is the elevation of home vs the campground? Did you have more wind one way vs the other? I doubt Tow/Haul has anything to do with your fuel economy while towing. Tow/Haul on might adversely affect fuel economy in a non towing trip.
Either use it or don’t, in your case, doesn’t matter. (Assuming you have a 6 or 10 speed F350)
Although even with a smaller load, T/H is nice if you’re up n down hills.
