Well you can't start out in 3. My 2011 will actually stay in 3rd gear even from a stand still. Working the same way it would if you put it in 2nd. Just stays in the selected gear.

So that leaves you two options... Put in Drive with tow haul mode and just drive. I read someplace and know that the Tow/Haul Mode takes throttle position and inclination angle to determine what gear it should be in so it is a relatively smart system. The other option is to manually shift the car through the gears, 1...2....3 and keep it there. I suspect that will defeat the whole purpose for the Tow/Haul mode as it won't select the proper gear (i.e. downshifting down a hill etc...) Not a good option because if you leave it in 3rd and slow down it will stay in third and lug the engine and overheat the transmission.

I can't figure out why 3rd gear stays in third gear all the time. I have never had a car work like this but mine has done that from the minute it came off the lot.

If someone can tell me that there is something wrong with my truck I would appreciate it, I just assumed it was designed this way. Never use it because it is functionally worthless IMO.

Just keep it in drive and make sure you use the Tow/Haul Mode.

Johnny