2012 Toyota Tundra 5.7 SR5 Towing Package
Hello, we have just purchased a new Toyota Tundra to pull our 25 foot Avion TT that weighs 7800 lbs (gross), We tried using tow haul switch and it seems to change back and forth even with a small hil...
Forum Discussion
I generally do not use Tow/Haul when towing. I would be interested to know more precise detail about what T/H actually does. Not much information available except that it changes shift points and the manual says you will get slightly poorer MPG in T/H.
In T/H the transmission will try to utilize 6th which at least in Colorado it cannot hold with even a slight incline. So it will unlock the torque converter which feels like a slight shift, and if that is not enough it will downshift to 5th. It might also lock or unlock the torque converter multiple times in 5th or even shift to 4th. For this reason I will generally drive with the selector in S5. The torque converter will stay locked up and there is not all the hunting around by the transmission. BTW even if you have T/H selected it is deactivated if you use S shift mode.
For engine braking on hill decent, I also don't find T/H aggressive enough for lower gear selection. I use S mode and select the gear that gives the necessary engine braking.
In T/H the transmission will try to utilize 6th which at least in Colorado it cannot hold with even a slight incline. So it will unlock the torque converter which feels like a slight shift, and if that is not enough it will downshift to 5th. It might also lock or unlock the torque converter multiple times in 5th or even shift to 4th. For this reason I will generally drive with the selector in S5. The torque converter will stay locked up and there is not all the hunting around by the transmission. BTW even if you have T/H selected it is deactivated if you use S shift mode.
For engine braking on hill decent, I also don't find T/H aggressive enough for lower gear selection. I use S mode and select the gear that gives the necessary engine braking.
