8% grades?

[Dave11]

On bigger grades I select the gear manually that way you don't get an unwanted upshift for a slower vehicle ahead or a sharper bend in the road. Also, use Tow/Haul when in mountains whether towing or not, makes a huge difference going downhill.

[nothermark]

Two things to keep in mind.

Tow/haul just changes the shifting pattern.

If you get stuck in too high a gear and stop all you have to do is to start up again to be in first. You may not get up to the same speed from a standing start that you had with some momentum going into the hill but you should be able to climb the hill in first or second and high rpms.

[Waiter21]

I'm not sure you can achieve 4500 rpm from a standing stop.. Thats why I say, don't stop, keep it moving and keep the rpms up high.. rpms is hp.

With full throttle, your engine will produce approximately twice the hp at 4500 rpm as it does at 2300 rpm..

[tiffy2000]

I have had the same issue with my 2000 V10 where it will upshift into a higher gear and then it won't downshift when I mash the pedal to the floor. Would the 5-star upgrade help these situations ?

[Sweetbriar]

The engineers who program the ECU try, but can't, program for every situation. The variables are just too much. This is why we still have the ability to take control of the transmission. The OP's situation, as described, is exactly why. Downshift as necessary to maintain speed. Keep the RPM up at least over 3500 where the engine has the higher HP/Torque numbers. Doesn't matter how many gears the transmission has or how many valves are in the heads you sometimes have to actually drive the thing to include manually shifting the gears.

Tow/Haul is a nice feature but its not a 100% replacement for the driver to manage the overall performance of the powertrain in unique and challenging situations. The higher RPM also has the added benefit of increased cooling since the water pump and fan speeds are directly related to engine RPM. Same for the transmission oil pump and moving fluid thru the cooler. Downshift, stay to the right, turn on the four way flashers, watch your temps and hang with the over the road truckers.

It maybe a race but with everyone going someplace different you'll still be the winner and first to arrive at your destination.