I have only pulled a 12' lawn trailer with some furniture on it without tow haul mode on and I was kinda dissappointed in the effort it took to accelerate. I could really notice the trailer was there. Finally when I came to a stop I switched to tow haul mode and it makes a huge difference. Accelleration was great and the feel of the trailer behind was much less.

I am just wondering if you can shift to tow haul on the fly or is it reccommended to be at a low speed or stopped completely?

 

I only use tow haul when pulling the boat (16 ft) going up and down hills and through town. It is nice that it downshifts going down hills to prevent brake usage. When running down the interstate pulling the boat I don't use it often. My truck doesn't hunt for gears except towing around the 55 mph range. Towing at 70 mph, pulls great. That's just me. I think the 3.92 help alot..
I shift on the fly when I need it, playing around town with higher shift points and the downshifting..

 

With lite loads, small trailers use common sense and check your trans temp and judge for yourself.I'd think under a 2k trailer would proberly be a no issue.I'd think with 3.21 rear gears I'd use it of OVER a 1000 LB trailer as that is a pretty tall gear.Understand T/H disables 5th gear.Turns 4th into a 1 to 1 instead of a overdrive gear and underdrives the other gears with 2nd having TWO ratio's. It does a LOT

 

I'd like to know that, too. I figure the best way would be to mess around with T/H by turning it on and off while cruising on the interstate and see what happens.

By the way, if T/H disables 5th gear, wouldn't running in a constant 4th at interstate speeds increase engine and tranny temps by running everything at a higher rpm? ( i mean, logically, the answer is no... but why not? )

 

It pulls easier.Less HP to move and hold speed with a load.

 

6 trips hauling my 19 ft Center Console boat about 2500 pds loaded .
Approx 2 hrs round trip.
Mostly highway with some hills (I live in CT)
I have towed with and without TH
Braking on tow haul is great especially on back road hills near my house.
I had better fuel mileage +.5 mpg using tow haul and a steady speed 65-70 mph.
I try and use it when I think about it.

 

When towing, you shouldn't be going that fast for it to be a concern. Besides, there are still a lot of 3 speeds and 4 speeds out there that do quite fine.

 

When ever I switch to t/h on the highway my Evic still says 5. Does it really shift into 4, or does it just lock the torque converter in 5? Guess I should try again and watch rpm's. I don't recall it changing that much, few hundred.
BTW, I switch all the time on the fly. Don't know why it would hurt since the truck automatically downshifts to pass.

 

I got back from my trip a few days ago. I ended up using the t/h for most of the time. Basically, it just seemed like the natural thing to do and felt better when the truck downshifted on the highway when I activated it on the fly, plus the downshifts while braking worked well, too.
Of course, this was mostly in my mind, i'm sure, because towing the 1200lb trailer felt invisible behind the wheel no matter what mode.
I guess at that weight it's a non-issue... the truck ran fine either way, just differently.
I will say one other thing though, my hand-calculated mpg was 13.1 for the trip where it is normally appx 15.5 without a load. Next time I will try not using t/h at all and see what happens. ( i did sit in 2hrs of traffic on the way and 1hr of traffic on the way back... so the data is kinda corrupt. )

 

I drive in tow/haul for city driving.Don't like when in MDS,and i want to give it a little gas [not enough to have it switch out of MDS mode]the truck bogs when in 4 cylinders.Willing to give up top gear ,for better responce in city driving.Hyway MDS not so bother-sum.Waiting for Diablo tuner for 2010 so I can shut down MDS but keep 5th gear.