Originally Posted by DocBrown
I think one of the reason many people don't consider them as tow vehicles is their low payload capacity. Other than that they are great trucks.
OK, I'm curious to understand what that means? A sealed system where you can't change the fluid yourself, at least not easily? Of is there some taboo about performing your work under warranty?
We're getting away from the OPs original question, but to answer the questions posed about the Tundra specifically:
The payload capacity of the Tundra, as with all trucks, is going to depend on the configuration. My double cab 4x2 is at 1595 lbs, so well over the 1/2 ton label it carries.
As far as the transmission goes, it's a sealed system that's not easily worked on. There is no dipstick to check fluid level and/or quality, though there may be a sight glass on the transmission itself - I haven't crawled under there to look.
I should also clarify that this is for the 2014 model year. I don't believe the power train has changed much over the last few years, but not positive.