I don't notice much of a difference. The truck had less than 300 miles when I drove it empty 700 miles to IN, then loaded it with a 3,600 pound camper and drove back 700 miles to SC. The only difference I noticed with the button pushed in was the truck slowed down going down a hill. In some cases I left the switch off to build up speed for the up hill run. There may have been a slight change in the shift points when acceleration but it wasn't noticeable.

So the question is do you drive with the switch off then push it in if you pick up too much speed. I never got to a long down hill run that required the Jake brake but I know there is a good chance it may be necessary when I drive from SC to NY

 

it should also shut off the overdrive to keep from burning it up, but yes it does change the shifts points a bit, and will downshift a lot sooner when you let off the pedal to help in slowing, i wouldnt pull real hard in overdrive, but it wont hurt anything to shut the tow/haul off to gain speen downhill, but the same thing could be accomplished by riding the throttle a little rather than shutting off the T/H

 

I am going to be taking I-77 to NY and there are a few long downhill runs in the Virginia area that can get a bit scary if you let the vehicle get get away from you. I like to avoid braking as much as possible and let the momentum on the down hill help me on the up hill and improve my MPG. I start off a few miles under the speed limit at the top of the down hill and don't use any braking I start down shifting before the truck gets dangerously over the speed limit. I get good MPGs with all the vehicles I own and my brakes seem to last longer than the average drivers so most of the time I go easy on my vehicles but don't pamper them. I don't drive like a little old lady all the time, I also like to get on the gas every once in a while even though it hurts the gas milage it's good for the engine to get a goo workout and it's fun. But if I am hauling a heavy camper with a lot of wind resistance on a 1,600 to 2,000 mile round trip I want to do what I can to improve my MPGs and coasting is one thing that has worked for me.

In my opinion the tow haul button slows me down too much but I wasn't sure if there is much of a benefit keeping the button in when accelerating. i wasn't aware of the issue of the overdrive shutting down.

I am going experiment an try driving with the button in and out and keep an eye on the transmission temperature.

I have been driving for over 45 years and hadn't thought about riding the throttle I like the idea a lot, No matter how old you are there is always something new to learn

 

Tow/haul shouldn't shut off overdrive if it works like the tow/haul button on the 4 speed autos in the 06 and early 07's. I have an early 07 and it changes the shift points a little, but more importantly it locks the torque converter in 3rd gear instead of after the shift to 4th gear. Locking the torque converter sooner keeps a lot of heat out of the transmission. I'd be willing to bet your 6 speed does something similar, but I don't know the specifics.

 

I took it for a short 80 mile ride today and the tac stayed at 1,500 at cruising speed regardless of the position of the tow haul switch so it looks like the O/D is not effected by the tow/haul switch. I think I am just leave the switch off unless I am in long steep hill or mountain areas