I wouldn't just drop a tuner because it doesnt provide you some eye candy. If they support trans tuning for the 2012's I would HIGHLY reconsider! My truck tows like a wet dream as compared to stock! That is...with the advanced trans software. It's a pain to set up initially but it makes it well worth it, plus you can limit or remove Torque management. These trucks are set at 80% TM(meaning only 20% power in the shift) This is why there's a massive delay shifting. My truck jerks my head back when shifting now. Again, makes towing much better.

What is a trans guage gonna do for you? Your not gonna stop towing..lol If your within weight limits and take the usual rests, your fine. If your worried about cooking the fluid, spend your money in a Deep tranny pan that has a drain plug and fins for improved cooling. That will do ALOT more than a gauge will.