The instructions you got for removal are spot on. I'd only add that I'd plan for some locking pliers to clamp the coolant and trans lines to prevent a bath.

But I doubt very much you will find an obstruction. Not in the trans fluid path, else you would have issues 24/7. And if you have coolant obstruction from deposits, I venture to say you have bigger issues, such as radiator.

Check also fmugar's posts about the radiator design and quirks affecting trans cooler efficiency.