Tow/Haul Button: What is it good for?

TimHolt · 10-09-2016, 12:19 PM

Harvey the RV, has a Tow/Haul button located on the shifter.

Since I don't tow/haul anything, I don't pay much attention to it. However, it got me wondering, are there times when I should use that option when driving, even if I am not towing anything?

**JFlightRisk** · 10-09-2016, 12:27 PM

The tow/haul mode changes the transmission shift points, to keep the engine RPM's at an optimal range for pulling or hauling heavy loads. It helps on hills, and acceleration so the engine doesn't bog. We use it every time the TT is hooked up.

justman · 10-09-2016, 01:10 PM

Not used except when towing. I suppose you can use it when hauling heavy loads in the bed to help with braking.

hoppers4 · 10-09-2016, 01:25 PM

I use it especially for downhill stretches. The transmission will downshift sooner and stay in a lower gear longer thus saving the service brakes. I can come off of such places as Mt. Hood with very little use of the service brakes.

Seann45 · 10-09-2016, 01:36 PM

Since your in a motorhome which is like hauling your house around, I would use it anytime your in hilly country.. probably would not hurt to keep it on all the time.. easier on the engine/transmission.

**norty1** · 10-09-2016, 01:39 PM

Even in our truck we use it when mountain driving to control down hill speed even when not towing . It saves the brakes.

**Mustang65** · 10-09-2016, 01:40 PM

Since you have a class "C" (correct?) and not a TT, all the weight you would be towing in a trailer is now on your "C" chassis. Using the tow-haul mode will help your engine/trans preform at its optimal range (as mentioned above) with all that weight.

I would be using it.

Don

abarkl · 10-09-2016, 02:11 PM

The owner's manual for your chassis should have instructions from the engineers who placed it there when and how to use the Tow/Haul button.

We have a diesel motorhome that is equipped with an engine exhaust brake. We use it to scrub small amounts of speed whether during a decent or sometimes will leave it on while driving in the city, to save on the wear of the service brakes as many others have mentioned. To scrub more speed, downshifting the transmission is what we use.

We also use the principal of whichever gear it took to get up the hill is the same gear that should be used to get down the hill.
We learned a hard lesson many years ago with our first gas motorhome that using the service brakes incorrectly would cost $1150 each time to replace the cracked rotors.

Dustdevil · 10-09-2016, 04:20 PM

Transmissions with selectable tow/haul mode have two firmware programs, which is what you are really selecting. In non-tow/haul, the transmission shifts smoother, but creates more wear and tear in the clutches. It shifts at a lower rpm for comfort, and to eliminate the "bump" into the next gear. There usually is no coordinated downshift when you contact the brake pedal in this mode. In Tow/haul, it's just the opposite. Comfort is sacrificed for reliability and wear/tear. Transmission shifts at higher rpm points, and they don't care much about comfort. They're trying to eliminate heat and wear from shifting slowly and slipping into the next gear. Like slipping the clutch vs just letting it out firmly. Selectable Tow/Haul is mostly for pickups hauling trailers, so the pickup can double as a comfortable daily driver in non-tow/haul mode. Your motorhome IS the heavy load, regardless of whether it's actually towing anything else. The Allison in the diesel Seneca motorhomes is the 1000-MH or 2000-MH, which is NOT selectable. It's ALWAYS in tow/haul mode. That's what I did with my older class C, and my pickup truck all the time. I didn't care about smooth slippery shifts. I cared about creating excess heat in my torque converter and transmission, or lugging the engine due to shifting too early.

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