Tow/Haul button: what is it for?

[510dogmom]

Hi all, very noob question.

Just purchased my second RV., 2012 24' Class C on E350. The tow/haul button automatically comes on when started. Sales person said to just turn it off. What is it used for? What is the best way to utilize this function.

BTW, last RV was a 2003 Winnie Vista -- this has the VW Eurovan chassis. I got this newer RV due to ex-husband getting the Vista and because I wanted an RV that anyone could fix.

[Lwiddis]

510dogmom, what did the Ford owners book say?

[DrewE]

pastorbillv wrote:

And, on flats, slight downhills when you're not working the engine with your load, turn off tow/haul and the let engine kick into "overdrive" and drop RPMS for fuel efficiency.

Tow/haul mode does not disable overdrive. It may make it a little slower to shift into overdrive (and probably less apt to shift out when not really needed), but it does not lock it out.

If the button is labeled "O/D Off" (i.e. you have the old 4R100 transmission or a predecessor), that does indeed disable overdrive, as labeled; but tow/haul is a different and rather more clever thingy.

[NMDriver]

From reading on the various truck modification forums it also helps win drag races although I have not tried that feature 🙂

[Lwiddis]

Are the above posts pretty much what Ford said in their E350 owner's manual?

[pastorbillv]

Desert Captain wrote: Anytime you are descending a long grade you should have the Tow Haul engaged. About the only time you don't need it is when lightly loaded and descending a very slight, 1 or 2 per cent grade or running on dead level terrain and no head wind.


Fully agree on both points.

You MUST use the engine on downhills or you'll burn your brakes up. In addition to tow/haul, I often manually shift into 2nd and even 1st depending how steep and how slow you're going. Just ride the engine downhill and touch the brakes now-and-then - DON'T ride them!

And, on flats, slight downhills when you're not working the engine with your load, turn off tow/haul and the let engine kick into "overdrive" and drop RPMS for fuel efficiency.

Bottom line is that with heavy vehicles you have to actively manage your transmission and braking. Consider your transmission as semi-automatic that needs shifting throughout your drive.

I almost destroyed my brakes on my Class C in Zion on its maiden voyage! Pulled-over and let them cool before realizing I was being stupid for not engine-braking!

Bill

[2oldman]

Google: tow/haul

[avan]

Per the owners manual...

[Sam_Spade]

DrewE wrote:
(I say "I would" because my motorhome is old enough to lack the tow/haul mode.)

And it works just fine without it.....right ??

My 28" has a 450 so the situation is slightly different BUT......I have yet to feel a real "need" to use tow/haul except descending long grades. Even when also pulling a small trailer.

The transmission downshifts when it needs to and it goes along just fine.

So my advice is: Try it without using tow/haul. If the engine seems strained and/or it downshifts often then try it.

If you are whizzing down the road and you think everything is fine.....then it probably IS.

[DrewE]

As others said, it alters the programming of the transmission controls to work better with heavy loads. Since a motorhome is always a heavy load, I would leave it engaged all the time. (I say "I would" because my motorhome is old enough to lack the tow/haul mode.)

Besides the shift points themselves, it tends to make the torque converter lock up more readily (I think) and may alter some of the details of the timing of the actual shifts in an effort to keep the transmission operating temperatures down.

[Desert_Captain]

For the record I too own a 2012 24' E-350 Class C that I have logged 35,000+ trouble free miles in over the last 3.5 years...

Anytime you are running anywhere near your GVWR or towing anything, you should have the Tow Haul engaged. Anytime you are descending a long grade you should have the Tow Haul engaged. About the only time you don't need it is when lightly loaded and descending a very slight, 1 or 2 per cent grade or running on dead level terrain and no head wind.

Tow Haul re programs the engines ECM {Electronic control module = co outer}, resetting the shift points, locking up the torque converter which eliminates friction which = needless heat making your transmission run significantly cooler and your rig run much more efficiently.

As you descend long steep grades in TH the engines compression acts to brake the coach and all but eliminating the need for braking and you will not burn a drop of fuel all the way to the bottom of the grade.

TH is probable the least understood and utilized function of any vehicle. Read your owners manual and know that the salesman you dealt with is an idiot.

:C

[DutchmenSport]

Tow/haul cause the transmission to shift at a higher engine RPM for each gear. When the vehicle is under a load (like towing), at slower speeds, the transmission will shift up and down way too much. Sometimes, the transmission will not down-shift at the right time to keep the torque up too if you do not have tow/haul engaged. When needing to speed up, and you're expecting a down-shift to occur, sometimes they just don't.

With Tow/Haul, the shift pattern is a bit different. The transmission will stay in lower gears longer, and when climbing hills, or towing a load, the transmission will (kind of .. sort of ...) lock into a lower gear to keep the torque up. Somehow, it knows how to do this.

So, if you are on hills or in town with lots of stop and go, tow/haul is great! If driving interstate, flat and steady, and shifting is minimal, then you don't need tow/haul activated.

Another advantage of tow/haul, that I find more beneficial that then different shift pattern, is the fact, when activated, and coming down mountain roads (interstates), tow/haul will keep your transmission in a lower gear without you having to manually down shift. The engine will rev, but it will keep you in a lower gear, thus prevent you from having to ride your brakes, or manually down shift.

Once you get to the bottom of the hill, press the gas peddle slightly, and it will then shift back up to the next gear. It's really sweet the way it works. I really couldn't tell the big difference until we hit the mountains of Virginia, West Virginia, Kentucky, Tenessee, and South Carolina that first time. And then .. Oh Wow!

Now, whenever I tow the trailer, I just automatically push the tow/haul button "on". Even on flat ground, in town, the higher shift pattern makes driving much nicer too.