Tow Haul

Just got back from 400 miles thru Northern Arkansas and Missouri. Used it the whole time. Transmission temps do drop when it is on vs when I don't use it. Unless I'm on a flat plain with a tail wind, it will stay engaged.

Mine is also on when I'm towing. I can't believe some are flipping it on and off so much. The 'extra' amount of fuel burned by increased shift points has got to be so miniscule (compared to the fuel burned by towing a brick!) that it isn't worth the worry.

Colo. newbie wrote:
Just wondering when to use Tow Haul? I know down hill is the best but any thoughts on the flat or uphill or just all the time?

Does your vehicle have an owner's manual?

Mine's on all the time when I'm towing. I don't bother trying to out think the engineers that built my vehicle and would rather use my brain power for things that I actually should be thinking about.

Whenever I tow it is on.
It helps keep the engine in the power band and helps with braking, especially in conjunction with the exhaust brake.

It will depend, like others said, your individual truck and what your owner's manual says. When I had my 2005 Chevy 2500HD I didn't use it much when I towed heavy, except when climbing hills. My particular truck did not have grade braking, and in hot weather the transmission would actually run 10-20 degrees hotter with tow/haul engaged. Other users have reported cooler trans temps, and grade braking would be a very useful feature, especially combined with an exhaust brake.

I use it always when towing (when I remember to push the button).

I turn Tow/haul mode on the minute I pull out. I will sometimes turn it off on long down hills if I have to shoot back up another one immediately. The D/A does too a job slowing truck down while descending grades that I have to sometimes accelerate to keep speed. Love my truck.

Had this discussion with a lady this morning when she asked when I used mine! I told here when starting from a stop loaded or trying to start up on a hill, even now with a motorhome. She said only to use for downhill according to a website she visits. I do sometime but not often as you can well control your speed unless on a long descent. Same on long climbs if you have the speed to carry you through.

T/H locks your trans and keeps the converter from shifting automatically. So that is why it is not needed on flat terrain or for all pulling duties unless you keep the truck/vehicle bogged down in slow speeds and low rpms. Have 04 F350 and now E450 and t/h seldom used on both. Read your manual, look for references but if you use t/h all time I believe you are wasting the fuel you are trying to save in the 1st place! Just my thoughts and yours may vary.

I would consult owner's manual. What others do (whether it's correct for them or they just think it is) really has nothing to do with what you should do. My owner's manual is clear that tow/haul is recommended only when exceeding 75% of gross weight. Or possibly in steep hill country. Otherwise I've noticed the engine just winds out needlessly and wastes fuel in tow/haul mode with no other discernible difference.

I rarely turn mine on. But then again I'm not even close to gross.

It gets really annoying when going down hill when it downshifts and then I have to add fuel over and over and over. In a 5K trip I can save quite a bit of fuel with it off.

In steep hills I will turn it on, but that's rare.