Tow/Haul button: what is it for?

Related to the above two posts ... as I mentioned before them in my post I had my failed E Series TorqShift transmission replaced with a heavy duty version of it. The replacement transmission felt immediately like another model of transmission was behind the V10 when in Tow/Haul mode.

I wonder what's going on? Maybe I wound up with a "pickup version" of the transmission? Or maybe my ECU detected something different in the replacement transmission's sensors' responses and adjusted it's transmission control algorithm accordingly?

Something is different - especially noticeable in Tow/Haul mode being smoother and less in-your-face with it's upshifts and downshifts. Full time Tow/Haul use is now very comfortable.

I don't doubt that the tune has made your (Awilson's) motorhome more civilized and nicer to drive. However, I think Brazel's was rather off base in their comments.

The version of the V10 used in the E series is quite different from that used in pickups (and in the F53 chassis); it has the older two-valve heads, while the other vehicles use 3-valve heads and produce significantly more power. (The E series chassis doesn't use the three valve head version due to space constraints, as I understand it; I guess the larger heads just plain don't fit in the chassis.)

It may be that the transmission is tuned for a "average" use of the E series chassis, which gets built into all sorts of vehicles: shuttle busses, box trucks, ambulances, and of course until rather recently plain old vans. The van bodies would generally be less loaded and have a good bit less air resistance than a motorhome.

Have you measured and verified the 50 HP difference? That seems like a rather large gain for only software changes, and would seem to me to imply the need for e.g. cooling system improvements.

My experience on a small class C was the Ford constantly shifted gears so I talked to Brazel's RV in Washington and they educated me on Motorhome engines. Ford produces an engine and transmission which is tuned to get the best mpg in a vehicle, which will be the vehicle they sell the most of. The pickup. The pickup does not run around with much of a load so just know your class C shift points are tuned for the best fuel economy and shift points for a pickup. I bought a ECM programmer from them and installed a tune specific to the engine and transmission in the Phoenix Cruiser I had at the time and what a pleasure it was to drive from then on. No constantly changing gears at the slightest grade, it added about 50 HP and a lot more torque and the torque converter stays locked up longer to reduce heat in the transmission. If you never go up and down hills you would not see any benefit but traveling through Colorado it was a joy and the TH still works awesome going downhills. After talking to Brazel's about why all the gear changing it all made so much more sense as to the why my Motorhome acted the way it did.

The 5R110 transmission in our 2005 E450 chassis (the first model year for the 5-speed, computer controlled Ford TorqShift transmission with the Tow/Haul mode) failed at around only 61K miles.

I assumed it would be a bullet-proof transmission in an under-loaded E450 chassis whether in Tow/Haul mode or not, so for overall smoothness in all driving situations except downgrades I never had it's Tow/Haul mode turned ON.

I don't know if my above usage made the transmission fail prematurely or if it was merely an early-life component failure. I had it replaced with a remanufactured heavy duty version of the 5R110 transmission. This transmission upshifts and downshifts so smooth with Tow/Haul mode turned ON - as compared to original one - that I now can leave it engaged all the time while still experiencing very smooth operation.

BTW, I'm speculating that with Tow/Haul mode engaged all the time ... gas mileage may actually be slightly better ... because of less clutch slippage in the transmission. Clutch slippage of course raises temperatures and it takes energy to raise temperatures. I have no data or proof of this ... but it just makes sense that fuel usage would be a tiny bit lower with less waste heat generation.

I also find tow/haul useful in heavy traffic because it keeps the torque converter locked, so the second I let off the gas, engine braking slows the vehicle.

Keep in mind that overdrive is not intended or designed to pull heavy loads where torque is needed. I would leave the transmission in tow/haul all the time. It will hurt your gas mileage but, save your transmission. It causes the torque converter to lock up more meaning cooler fluid temps and it locks the vehicle out of overdrive. On my Suburban I leave the tow/haul off when not pulling the camper and it's always on if the trailer is hooked up.

One note of warning: With tow/haul on leave the cruise control off while climbing hills and mountains. The vehicle will try to maintain speed and in tow/haul it will get super weird on downshifts. When I'm in tow/haul I just leave the cruise off period. The cruise control computer doesn't care about the transmission, it just wants to maintain speed. The transmission tries to oblige by down shifting. If the vehicle is in tow/haul and in 3rd gear (locked out of overdrive), and the RPMs are already in the mid range but the speed is dropping, the cruise will force it to drop another gear. So, the RPMs will be near redline into the 2nd gear shift and that's a lot of torque and horsepower hitting that transmission and drivetrain. Better to control that with your foot and let the speed slip a little rather than hurt your expensive RV. Tow haul is great, awesome but, you be in charge not the cruise controller.

cross21114 wrote:
If you have a Majestic, is it a used Cruise America rental? We rented one in April and the tow/haul mode was modified to be "on" when started. You had to manually turn it off.

Interesting.... I always make a point of talking to folks in rental Class C's. Spoken with dozens and not one had ever even heard of Tow haul. Now if everyone, or most everyone, who rents is running without any knowledge and obviously the use of TH then those rentals are seriously cooking their transmissions. Just another reason I would never consider buying a used rental {but I digress}.

Perhaps some of the rental outfits have figured out it is easier/better to just have the TH come on automatically rather than expect a renter to figure it out/remember to turn it on. Given that the rental units aren't kept for more than couple of years the damage that is done by not using TH probably doesn't show up until they are sold and down the road.

On the topic of why you might not want to buy a rental.... every time a C lass C blows by me doing 75 - 80 and it happens all the time, it is a rental. Most folks renting don't have a clue how to drive them, think they are in an SUV on steroids and drive accordingly. They also have no clue as to how the systems {AC, generator, refrig, water heater, furnace etc., etc..} should work.

If you want to buy a Class C cheap then a used rental is certainly an option but you have no clue what you are getting. Chances are it has been seriously abused. If it has worked for you, hooray but IMHO, it is a high risk, limited reward venture at best.

As always.... Opinions and YMMV

:C

If you have a Majestic, is it a used Cruise America rental? We rented one in April and the tow/haul mode was modified to be "on" when started. You had to manually turn it off.

"Salesman didnot provide any manuals. My rig is also a Majestic 23 A"

Very surprised you couldn't find it on-line. You'll need it for multiple reasons including maintenance recommendations, electronics etc.

http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/12ecoog1e.pdf

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.

If it is working right that should NOT be necessary.
It will do all of that anyway, maybe just a slightly higher speed.