If it were me...
The John Wood or BTS are nice, but very costly. If you have the extra money and you want to keep the truck, go for it. But for me, that's kinda like something I'd do when/if I had to.
So, if it were me, I'd keep running with what you have and lose the concern over this one time incident. Drain and replace the fluid at the same time you're adding a transmission cooler. If your SD is one of those that doesn't route to a separate cooler or to the radiator, then you'll need to purchase a bypass valve kit and new SD cooler lines. In my opinion, skip the 6.0 cooler and go with a much more affordable Tru-Cool Max (for less than half the price). This is a relatively simple mod, but you'll lose fluid in the process, which is why I recommend changing it at that time.
With my 96 F350 E4OD, I haven't seen 180 degrees since installing the Tru-Cool Max, regardless of what I've hauled or what the ambient temp is.
