using a 13" ring gear in the axle thats rated for a max of 35,000 pounds with a dually? need to step it up there.
also need to get the price figured out as well. the cheapest tundra i've seen at a lot (new) was listed at 41,000, not the fully loaded model but nice. fully loaded i've seen listed at 55,000 for a tundra 1/2 ton, thats as much as a fully loaded chevy/gmc 1 ton crew cab dually with the duramax/allison combo, not much less than a dodge or ford equally equipped vehicle. diesel engine usually runs a premium of about 5k dollars with the good tranny behind it over an equivelant gasser model, plus about an extra 4k per additional weight rating (1/2, 3/4, 1 ton). so going off of current figures that would put the tundra 1 ton dually fully loaded with the diesel at 68,000. less power, most likely less fuel economy being an 8L motor compared to a 6.9L, 6.4L, and 6.6L, and a wider gear spacing in the tranny because of fewer gears (or a loss of granny gear which would absolutely kill the heavy towing capability). with that price tag and those features i dont see it pulling very many people from the big 3 who actually use the truck for what its built for (towing).