Adding a transmission cooler

pxt wrote:
Adding a transmission cooler..does it add towing capacity?

Only if transmission temperature is the limiting factor for tow capacity. If the limiting factor is frame strength, then no, it won't increase your tow capacity.

How would you determine what the limiting factor is for your vehicle? The only way I know to do this is to be part of the development team that develops the vehicle for production. NOBODY publishes this information.