Long Uphill Pull

Thanks for the input. Flip

Pick a gear that makes your engine happy. Not lugging or revving at red-line. The drive-train will run cooler if you rev enough to move air with the fan and circulate water. I have a 6-speed and use all 6 depending on conditions. Have fun.

I would pick a gear that lets you pull with a steady speed with the transmission locked up. Try to use the same gear or even lower when going back down.

When I had my truck and TT, my truck didn't have the T/H feature so I would do as smkettner said and keep the rpms up around max torque... in my truck that was around 3600 rpms. In my experience, it was the trans temp that I really had to watch rather than the engine's.

Ron

Put it in T/H and let the truck decide.

Use the gear that keeps you up close to 4000 rpm.
Use the lever to minimize hunting, especially at full throttle.

Put the transmission in drive (overdrive off) and use tow/haul mode. I suspect the truck's computers will select second gear uphill, which means you should also probably use 2nd gear down for the engine compression braking.