What the heck is Tow/haul for?

Have you read the owners manual? I think I would trust it more than anecdotal explanations from anonymous folks who may or may not know. Trust me it is in there.

rdhetrick wrote:

gmcsmoke wrote:
why would you take delivery on a vehicle you're not familar with? The salesman should have explained the trucks features or at a minumum you should have asked.

I love extremely helpful comments like this....wow....

Yes, it doesn`t answer the OP`s question, but it is a good question!

And as others have said the Tow Haul changes shift points, and TC lock up and it can help with engine braking. so when towing hauling use it.

gmcsmoke wrote:
why would you take delivery on a vehicle you're not familar with? The salesman should have explained the trucks features or at a minumum you should have asked.

I love extremely helpful comments like this....wow....

The manual should explain. The obvious answer is it's for towing and hauling with the truck as opposed to driving it empty to the store.
Engage it when the truck is being used "like a truck" to move heavy things.
The shifting will improve, you may see lower transmission temps, and it will help control your speed going down hill.

why would you take delivery on a vehicle you're not familar with? The salesman should have explained the trucks features or at a minumum you should have asked.

Exactly what he said, but also helps slow the combo down by downshifting when you go to stop, thereby helping save the brakes.

Specifically for moving a load it changes shift points and keeps the torque converter locked to avoid slippage which can make the trans overheat. I use it always when towing. I have a trans temp gauge and can see the temp rise if it is not engaged.