..... how does it work? Its like it has an exhaust brake on it. Any one know how it works?

Thanks

 

All just programming. Holds revs till 2500 and downshifts when you hit the brakes. No exhaust brake.

It also boost the pressure in your tranny.

 

OIC, thanks!

 

It also closes the vane on the turbo which acts like an engine brake.

 

<TABLE style="WIDTH: 669pt; BORDER-COLLAPSE: collapse" border=0 cellSpacing=0 cellPadding=0 width=892 x:str><COLGROUP><COL style="WIDTH: 669pt; mso-width-source: userset; mso-width-alt: 32621" width=892><TBODY><TR style="HEIGHT: 76.5pt" height=102><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 76.5pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl24 height=102 width=892>From the 2004 WSM I think I "re-typed" it all correctl;y):
The Tow Haul feature was designed to assist the driver when towing a trailer or a heavy load. All transmission gear ranges, including all five forward gears, are available when using the tow haul feature. The tow haul function is activated and deactivated through a switch located on the end of the shift Overdrive lever. The indicator light that is located at the end of the shift lever will illuminate when the tow haul driving. is activated and will go off when deactivated. On some models, the indicator light is located on the instrument panel. With the tow haul activated, the transmission will have the following features:</TD></TR><TR style="HEIGHT: 25.5pt" height=34><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 25.5pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=34 width=892>• Shifts will occur at higher vehicle speeds for a given accelerator pedal position to improve vehicle acceleration, reduce excessive shifting and increase the coast braking capability.</TD></TR><TR style="HEIGHT: 25.5pt" height=34><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 25.5pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=34 width=892 x:str="• The torque converter will lock up at lower vehicle speeds than normal with a given accelerator pedal position to improve transmission cooling and efficiency. ">• The torque converter will lock up at lower vehicle speeds than normal with a given accelerator pedal position to improve transmission cooling and efficiency. </TD></TR><TR style="HEIGHT: 25.5pt" height=34><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 25.5pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=34 width=892>• Upshifts are temporarily delayed while decreasing accelerator position during hill cresting to reduce excessive transmission shifting and to prepare for a possible grade braking downshift event.</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 12.75pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=17 width=892>• Engine braking is provided in all forward gears without the requirement of moving the shift lever.</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 12.75pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=17 width=892 x:str="• Manual 1, 2 or 3 will still be available. ">• Manual 1, 2 or 3 will still be available. </TD></TR><TR style="HEIGHT: 25.5pt" height=34><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 25.5pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=34 width=892>• Grade braking downshift feature provides increased coast braking automatically to assist driver in maintaining desired speed while descending a grade. This reduces duty cycle on the brake system and increases brake pad longevity.</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; HEIGHT: 12.75pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl26 height=17>• Grade braking downshifts are automatically commanded when:</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 12.75pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=17 width=892> — positive vehicle acceleration is sensed (natural acceleration from grade descent).</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 12.75pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=17 width=892> — a near zero accelerator pedal position is obtained.</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 12.75pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=17 width=892>— a minimum amount of time has expired since the last grade braking downshift.</TD></TR><TR style="HEIGHT: 25.5pt" height=34><TD style="BORDER-BOTTOM: #ece9d8; BORDER-LEFT: #ece9d8; BACKGROUND-COLOR: silver; WIDTH: 669pt; HEIGHT: 25.5pt; BORDER-TOP: #ece9d8; BORDER-RIGHT: #ece9d8" class=xl25 height=34 width=892>• Grade braking downshift mode is immediately exited should the tow haul mode be deactivated or if the accelerator pedal is depressed beyond a minimum threshold.</TD></TR></TBODY></TABLE>

Mark - Please correct me if I got anything wrong (I seem to recall past discussions on the torque converter lockup).

 

Does it do the same thing on the 08s? I drove my buddys 08 while towin a trailer and everytime the tow and haul button was activated and would depress the brake it would down shift. But ive never towed with my (new) to me 6.0. yet..

 

Depending on the speed vs. rpm's it will down shift. and the harder the braking the the more aggresive it is at getting into lower gears. I really like this feature and found the only negative side is to be careful in a hard rain, and of course snow and ice. it will have you sliding in these conditions. I just learned to not use it under those conditions. I havn't seen any details about its shift detection probably a computer software secret, so the best way to learn it is by just driving and expermenting.

 

No, it does not boost pressure in the trans. There is no need to boost pressure. The trans always has enough pressure to hold whatever torque the engine is producing.

I think that table is correct. The effect on lockup changed year to year. Manglement couldn't decide what we should do, so we had to keep changing what it did to meet their requirements at that time.