Tow haul mode

[Tequila]

I am sure this has been discussed before, but who uses it and how? I have a 1 ton diesel dually and will be towing a 5500 lb (dry) trailer. I am assuming it will lower fuel economy? Am I correct in assumign i shoudl probably turn it off on relative flat terrain and engage it in hilly terrain. So far I have tended to use it only for goign down steep grades so it downshifts when I brake.

[Monaco_Montclai]

yep, u need to read the book on it.mine keeps the tranny in a lower gear, just a bit longer to get all the mass of the rv moveing, then it shifts, works for us. now its all happy-camping

[Steeljag]

I have it and use it, and It does not lock out 6th gear (on my year / make). I do live in the flat lands of Florida, but have concurred Mt. Dora several times!

[brulaz]

When towing I put it in tow/haul. Haven't noticed any difference in mileage, but haven't looked closely either.

On my truck, in addition to changing the shift points a bit, it keeps the torque converter locked up between shifts which reduces over-heating.

Also like it for the automatic engine braking, keeping the brakes cooler. Can't imagine the additional wear from decelerating on mountain downgrades is significant, but then I don't live in the mountains.

[EcoBullet]

Skid Row Joe wrote:
do not use that button to downshift the rig to brake it's speed. Use the foot brake, by a push and release methods so as not to burn up the brakes with a constant push on them. The transmission will wear adversely if you try using it as a braking device, especially on those long, steep grades.

I'm no expert, but this is just about backwards of what I've always read, and done myself. I think I've even read in an owner's manual or two that you should downshift when descending hills to allow the engine to brake, rather than overusing your brakes. If you go down much of a hill and don't use any sort of engine braking, you stand a good chance of brake failure due to overheating, even if you do push and release. Your method might work in Texas, but please don't try that in the mountains of Colorado.

[Dog_Folks]

Skid Row Joe wrote:

Tequila wrote:
I am sure this has been discussed before, but who uses it and how? I have a 1 ton diesel dually and will be towing a 5500 lb (dry) trailer. I am assuming it will lower fuel economy? Am I correct in assumign i shoudl probably turn it off on relative flat terrain and engage it in hilly terrain. So far I have tended to use it only for goign down steep grades so it downshifts when I brake.

If your load / road speed conditions are such that the transmission is shifting back and forth rapidly - use the tow mode by locking out the Overdrive. Also, do not use that button to downshift the rig to brake it's speed. Use the foot brake, by a push and release methods so as not to burn up the brakes with a constant push on them. The transmission will wear adversely if you try using it as a braking device, especially on those long, steep grades. Better yet, get a Jake Brake on your engine - now that's pure cool there!

Well said. My trucker dad always told me that brake shoes were much cheaper than transmissions. Use the brakes.

[Skid_Row_Joe]

Tequila wrote:
I am sure this has been discussed before, but who uses it and how? I have a 1 ton diesel dually and will be towing a 5500 lb (dry) trailer. I am assuming it will lower fuel economy? Am I correct in assumign i shoudl probably turn it off on relative flat terrain and engage it in hilly terrain. So far I have tended to use it only for goign down steep grades so it downshifts when I brake.

If your load / road speed conditions are such that the transmission is shifting back and forth rapidly - use the tow mode by locking out the Overdrive. Also, do not use that button to downshift the rig to brake it's speed. Use the foot brake, by a push and release methods so as not to burn up the brakes with a constant push on them. The transmission will wear adversely if you try using it as a braking device, especially on those long, steep grades. Better yet, get a Jake Brake on your engine - now that's pure cool there!

[fla-gypsy]

My mileage goes down with T/H and I only use it when I want the engine braking assistance. I have plenty of horsepower and torque to move my TT adequately without changing shift points.

[hmknightnc]

Old-Biscuit wrote:
Yes it has been discussed....most recently LINK

Turn it ON
Try it out...towing or not
Read your manual about it's function/use

Push the dang button....you know you want to :B

X2, read your manual and turn it on. BTW I get slightly better mileage with it on not towing then with it off

[TucsonJim]

From my understanding (which may be flawed), it does not decrease fuel milage. It changes the shift points to shift at a higher RPM to prevent transmission hunting. It also allows for more aggressive down-shifting when going down hill.

Anytime I'm towing, I use the T/H button. However, most of my driving involves mountain grades.

[Old-Biscuit]

Yes it has been discussed....most recently LINK

Turn it ON
Try it out...towing or not
Read your manual about it's function/use

Push the dang button....you know you want to :B