TOW HAUL MODE?

scott19677 · August 19, 2014

Can someone explain what exactly goes on with the transmission, converter and computer when the tow haul mode is activated. I would like to carry over some of these characteristics and better drivability when I get a tune. I like how it holds gear longer and a little more aggressive with the downshifts. Explain like Im 5.

Archaic2021 · August 19, 2014

Mostly all in the transmission. It hold gear longer to keep the engine higher in the rpm range producing more power. More power, more pulling. Wont' put such a strain on the engine at low rpms.

Same way when de-accelerating. When the engine is at higher rpm's and in gear it acts as a brake kinda...let the engine slow you down instead of re-lying all on the brakes.

To my knowledge anyways.

scott19677 · August 19, 2014

Yeah , but I mean exactly it is doing mechanically. Say the converter, if and when it is locking up. Shift points, ect. I would like to have some imput when I get my tune. The things you mention are characteristics that I like about it. I just want to know what is going on inside the transmission and computer.

soltys · August 19, 2014

Like Archaic said - it's staying in the needed gear to keep the motor in the power band. (mechanically keeping the transmission in a lower gear to keep the motor higher in revs)

BigBadSierra · August 19, 2014

They usually increase the line pressure for better shifting under load as well.

newdude · August 19, 2014

Tow/haul mode is a function within the vehicle's software/calibration that optimizes transmission gear selection for operation during towing or with heavy loads. This optimization includes improving acceleration performance during launches, reducing shift busyness, assisting brake performance and speed control during engine braking situations, and improving vehicle speed control while requiring less throttle pedal activity.

In general, tow/haul mode maintains lower gears longer and increases shift pressures. It is designed to be most effective when the vehicle and trailer combined weight is at least 75% of the vehicle's Gross Combined Weight Rating (GCWR). Operation of tow/haul in a lightly loaded or non-loaded vehicle will not cause damage. However, there is no benefit to the selection of tow/haul when the vehicle is unloaded, and use of tow/haul mode during unloaded driving conditions will decrease fuel economy and may generate shift feel concerns.

FishinCricket · August 21, 2014

It'll also cause your blinkers to blink more (6 times instead of 3) when utilizing the "lane change" feature of the blinker...

But I know this wasn't even part of your question, really. lol

DJayx · August 22, 2014

It'll also cause your blinkers to blink more (6 times instead of 3) when utilizing the "lane change" feature of the blinker...

But I know this wasn't even part of your question, really. lol

NEAT!!

CANDenali · August 22, 2014

Hmmm does it do anything for 1/4 mile times?

Sent from Windows Phone.

FishinCricket · August 23, 2014

Most likely

jocassee · August 23, 2014

It also helps if your driving in mountainous roads.

KARNUT · August 23, 2014

I have a can tune , sometimes I put in tow haul when I nail it so it shifts to second gear at 5500 RPMs instead of 6K and a little softer. Then I'll turn it off for the 2-3 shift where the extra RPM is more useful. Yea I like to play.

CANDenali · August 24, 2014

Sweet. I've never towed anything so I was kind scared to hit the button to be honest.

Sent from Windows Phone.

GRN69CHV · February 9, 2015

Want to bring this back up. I've been experimenting with both driving in M5/Regular Mode and Drive/TowHaul Mode on my daily driving. What I've found is in M5, the motor always operates in V8 mode with smooth shifts etc. Fuel economy suffers a little. In Drive/TowHaul Mode, Motor revs out in 1st and 2nd them settles in 3rd and 4th, only dropping into 5th at about 50 mph or so. Didn't get it much above that on the driving I tried so not sure when it would drop into 6th. Here's the kicker. It stays on V4 mode a lot in 3rd and 4th gear. With the 3.08's out back, this has been a disappointment for me in regular driving with the both the trans and motor hunting up/down in rural driving. In tow/haul, this thing gates along nicely in V4 mode. Add in the trans braking (which I do like, reminds me of driving a stick), I think I have found the operating mode that I will use going forward. Short time I was driving it (about 15 mile round trip) the 25 mile avg increased about .5 mpg. I am guessing V4 mode is programmed to only engage in drive (either mode) or M6 when in manual mode.