We went out and made a few passes with the gtech last night. I noticed that my truck was quicker in the quarter mile with the tow haul on. The truck catches second pretty good too with it on, while in normal mode I never catch second. My questions are does anyone else get better times with the tow haul on, and will it hurt my tranny to race it in tow haul if it is posting better times? My 15.4 at the track was with the tow haul on, so I just need to know if it will hurt my truck. I guess it will be shifting better when I get the shift kit in, but until it comes in....

 

IMO it is fine uless you have turned up the line pressure with something else, for ex. predator,HPPIII,edit, or a shift kit. if you have done any of these mods i would not recommend putting the trans in tow/haul. tow haul increases the line pressure to the trans. so if you do tow/haul and one of the other mods it will be to much line pressure, thus distroying the trans.

 

Yeah, I think tow/haul raises the line pressure in the trans, so that explains the shifting.
Does anyone know what tow/haul does to the shift points?

 

i believe it shortens them up. i remember that when i did it with mine, it shifted sooner. but i dare not do it now so i cant back it up.

 

i also think it shortens them. i changed all my shift times and points in the performance mode aka(tow/haul). so that it is kinda like a tow haul *** button like we talked about a while back.

 

I think that tow/haul mode also has an effect on torque conver lockup. It definitely does with the allison transmission, but I think has an effect on the 4 speed transmissions as well.

 

From looking at Edit, the only things I have seen is that it raises shift points....so it can hold the gear longer, at least under part throttle...WOT it doesn't raise them that much. It also increases base line pressure across the board, but it does not however increase it anymore than what the max is during regular operation. The max line pressure is still 90 and neither one go over that value, it just increases it slightly vs TPS.

From what I can tell thats all that it does.

 

... so in short it is ok... even with say, HPP3?

 

I don't know what the handheld programmers do completely....so I don't know....maybe the HyperTech/Diablo/SuperChip guys could tell ya.

Anyone downloaded one of their programs from a truck by using Edit?

 

1LEThumper... i never noticed you were from indy before... i'll be there with my truck in april... maybe we could take a trip to speedway, and do some runs...