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**Jlawles2** · 04-08-2022, 01:26 PM

Not speaking for the Ford programming, but the Chevy/Gm programming tends to hold the shifts a bit longer going up and shifts faster on the down. On the up side (acceleration) this is done to assist in increasing line pressures to the trans resulting in a fit firmer more crisp shift between gears for clutch life. On the down side, it holds gears in some instances to avoid over shifting (excessive gear hunting) as the engine lugs slightly when say pulling a hill or small changes in speed, but may shift early in say a breaking situation to help with slowing the trailer.

Next time monitor loaded and unloaded shift points. I did a similar test in my 2500's (GM) by setting the cruise to 65 mph, then on acceleration resuming the set speed at say 25 mph and monitoring the up shift points in both RPM and MPH. I chose this method because the ECU performed in a repeatable manner each time during the 40mph speed increase.

**Schiefswret** · 04-08-2022, 02:28 PM

Gotcha. Much thanks Joe.

**wygieman** · 04-09-2022, 01:28 PM

Originally posted by Schiefswret View Post

A couple of times in the past year or two I’ve pulled away towing my 28ft TT at about 6k lbs but realized several miles down the road that I failed to place it in Tow Haul mode. I thought to myself, hmm, I didn’t notice any difference in gaining speed nor any difficulty pulling until several miles down the road so I experimented a few times and realized a 1-2 mpg increase when leaving it in Standard mode rather than Tow Haul. Wondering if anyone has had a similar experience or has some input as to how this could be possible. All input appreciated.

I have always just assumed that the engineers program the transmission to shift on the torque curve (maximizing torque) in tow-haul mode, and on the fuel economy curve (maximizing fuel economy) when not in tow-haul mode. If you don’t need the extra torque, maybe you do realize the value of the fuel economy optimized shifting. I have no real knowledge about how it works, though.

**familytruckster4** · 04-09-2022, 01:38 PM

Tow haul changes the mapping on many aspects of the truck, some not as noticeable as others.

**Cate&Rob** · 04-09-2022, 01:42 PM

Hi Dave,

With my Ecoboost F150, I always towed in Tow/Haul mode and in 5th gear. (6th locked out) This kept the engine at the low end of the boosted RPM range where it felt more comfortable and prevented downshifts on moderate grades.

With the diesel F350, I also set Tow/Haul but didn't like the 10-8 downshift so I locked out 10th gear. (9-8 is much more comfortable) Hauled about 1400 miles like this. (Ontario to Florida)
On the return trip, I did not use Tow/Haul but still didn't like the 10-8 downshift . . . so I locked out 10th again. I could not sense any difference in engine/transmission performance with or without Tow/Haul . . . but, this could be because the diesel has way more torque than needed for more-or-less level towing with an 11,000 lb trailer.

Rob

**Guest** · 04-09-2022, 01:42 PM

Engineers don't always get it just right but tow haul is the best use of the powetrain for best performance. It's calibrated toward the high end of capacity where lighter loads would operate better with tow haul turned off. All the speed matching and downshifting to help save brakes makes tow haul a valuable feature to use.

Jim

**Schiefswret** · 04-09-2022, 01:45 PM

Thanks to all for the input.

**Dave27** · 04-09-2022, 02:46 PM

Originally posted by Schiefswret View Post

A couple of times in the past year or two I’ve pulled away towing my 28ft TT at about 6k lbs but realized several miles down the road that I failed to place it in Tow Haul mode. I thought to myself, hmm, I didn’t notice any difference in gaining speed nor any difficulty pulling until several miles down the road so I experimented a few times and realized a 1-2 mpg increase when leaving it in Standard mode rather than Tow Haul. Wondering if anyone has had a similar experience or has some input as to how this could be possible. All input appreciated.

I started towing on a regular basis not using Tow/Haul. It does seem to increase the mpg. When in Tow/haul mode, it takes longer to shift, and the rpms are higher when cruising at highway speeds. These seem to cause the lower mpg. I use the Tow/haul in steeper terrain, in stop and go traffic, and when maneuvering in a campground.
Dave

**howson** · 04-09-2022, 02:48 PM

Originally posted by Cate&Rob View Post

With the diesel F350, I also set Tow/Haul but didn't like the 10-8 downshift so I locked out 10th gear. (9-8 is much more comfortable) Hauled about 1400 miles like this. (Ontario to Florida)On the return trip, I did not use Tow/Haul but still didn't like the 10-8 downshift . . . so I locked out 10th again. I could not sense any difference in engine/transmission performance with or without Tow/Haul . . ...

Did you happen to compare fuel mileage?

**Guest** · 04-09-2022, 02:55 PM

It's a balance. I will use regular mode in the campground to force an upshift to keep the noise down. Using tow haul on some hills I'll throttle past the cruise setpoint to force an upshift as well so the shift maps while being good are not always perfect. My father's E350 will never upshift unless you back off the throttle then tip back in where it will hold in the next gear. No tow haul used on his rig. Poor trans calibration at best, but the 5.4 gets good mileage.

Jim

**Cate&Rob** · 04-09-2022, 06:46 PM

Originally posted by howson View Post

Did you happen to compare fuel mileage?

I did (of course

) track fuel usage.
10.5 MPG Ontario to Florida. (Early February)
12.5 MPG Florida to Ontario. (Late March)

I attribute the much better mileage on the second trip to warmer temps and the Diesel engine being more broken in.
There may have been a small contribution by not selecting Tow/Haul . . . but I could not feel a difference and most of the miles are steady state 9th gear.

Rob

**Guest** · 04-09-2022, 07:35 PM

Engines will continue to break in up to around 10k miles. It's also good to occasionally move to wot where friction varies across RPM ranges.

Jim

**DarnDave** · 04-09-2022, 10:13 PM

Everyone knows its downhill all the way from Florida to Ontario. Seriously, though, I use tow/haul for acceleration, I usually tow at 62 or 63 mph with cruise control on level or mostly level interstates. At that speed, I disengage tow/haul to enable an upshift to 6th gear, which otherwise wouldn't happen until 66 mph. I never use cruise on hilly terrain, and if I need to cancel the cruise I re-engage tow/haul. I also use the manual mode of the transmission when descending steep grades, and shift proactively as needed (truck driver in previous life). I feel the cruise + exhaust brake over revs the engine on some downgrades. Selecting the manual mode prevents this. Fuel economy can dip under 8 in mountainous areas, can be as good as near 11 if it is all flat. On a long trip, I use the trip B for fuel economy number from when we leave home to when we return. Trip A I reset at each full fillup. Last year's Bakersfield to Minnesota round trip of 5600 miles, we got 10.7 for the trip.

**Schiefswret** · 04-10-2022, 08:30 AM

Originally posted by howson View Post

Did you happen to compare fuel mileage?

No, Waiting to go on next trip.

Announcement

Standard/Regular mode vrs Tow/Haul mode, is this crazy?

Standard/Regular mode vrs Tow/Haul mode, is this crazy?

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