Tow Haul
Just wondering when to use Tow Haul? I know down hill is the best but any thoughts on the flat or uphill or just all the time?
Forum Discussion
Tow/haul mode is designed to minimize slipping of the torque converte and heat buildup in the transmission. It changes the points at which the converter unlocks and the shift points for the transmission.
The engineers at GM and Allison recommend using tow/haul when the total weight of the trailer and truck exceed 75% of the Combined Gross Weight Rating for the truck. For a GM 2500/3500 truck that is a trailer load of more than 11,000 lbs., and for lighter trailers it does not hurt anything or help anything to have tow/haul mode engaged.
The flash point for ATF is more than 350 degrees and if your fluid is at or below 220 degrees it is operating within its capabilities. GM specifies ATF service intervals based on type of duty and it can reduce the ATF change interval by up to 75%, though for general towing it changes it by 50%
If you are concerned then the next time you have the ATF changed swithc to a TES-295 grade of ATF such as TranSynd.
At least for the GM trucks the tow/haul mode and the grade control function only works in Auto. Put the transmission into 4th or 5th gear and the trans will still downshift but you have disabled grade control completely.
The engineers at GM and Allison recommend using tow/haul when the total weight of the trailer and truck exceed 75% of the Combined Gross Weight Rating for the truck. For a GM 2500/3500 truck that is a trailer load of more than 11,000 lbs., and for lighter trailers it does not hurt anything or help anything to have tow/haul mode engaged.
The flash point for ATF is more than 350 degrees and if your fluid is at or below 220 degrees it is operating within its capabilities. GM specifies ATF service intervals based on type of duty and it can reduce the ATF change interval by up to 75%, though for general towing it changes it by 50%
If you are concerned then the next time you have the ATF changed swithc to a TES-295 grade of ATF such as TranSynd.
At least for the GM trucks the tow/haul mode and the grade control function only works in Auto. Put the transmission into 4th or 5th gear and the trans will still downshift but you have disabled grade control completely.
