Towing with a tundra in the mountains

Welcome to the Forum,

A little more information would greatly be appreciated so that we can maybe give you a little advice from experience. Which engine in the Tundra? Gearing (if Toyota offers multiple). Trailer Make Model and GVW.

A 30' TT only weighs 6400 lbs? That sounds like a mythical dry weight. It can be done but will work very hard.

Tell me how you're not overloaded pulling a 30' trailer with a Tundra?

Depending on where your headed, here's a link with some details on the mountain pass grades and altitudes.

https://www.codot.gov/travel/maximum-grades-on-colorado-mountain-passes.html

Put the tow/haul on and let it go. It will pull that weight all day long without issue. Don't be afraid of the high RPMs in the mountains, that's where the power is. Sounds loud but won't hurt anything. You may need to manually shift to a lower gear downhill if the engine braking isn't enough.

I've pulled some steep grades with my old Tundra and an 8k tt without issue. It pulled hard and could accelerate and keep speed with traffic easily. It did a much better job than my current Ram 2500.

Towing 6500 lbs. won't be a problem. We went to the Grand Tetons, Yellowstone and Glacier last year and I was pleasantly surprised at how well the Tundra pulled our trailer.

Just settle in at 3200 to 4500 rpm going up or down the steeper inclines and you will be fine there. Pull the lever to hold the gear and avoid hunting. Don't be in a hurry and the drive will be easy.

If you have the big motor you will have sufficient power. You will burn a good bit of fuel but the Tundra does that even when not towing.

Just manually down shift going up and coming down. Let the engine do the work.
You will be ok.

What's in the truck? Cap, weight of passengers, etc? I think you will be burning a lot of fuel and be in 3rd gear a lot. I had trouble climbing some smaller wisconsin hills with the truck loaded with the family and similar sized camper.