Wow guys, thanks for all the replies. A little update as I've been researching the past day.
First and foremost, I posted this on the Ford Truck Enthusiast website as well, and curiously got a reply similar to SLE's post where a guy with a Class C that ran the Ford engine/transmission did a similar thing when backinup up a somewhat steep grade after driving all day. He was told by a local Ford dealer/mechanic that the Fords that run the similar setup as my F350 can "vent" transmission fluid that way. It sounds like I might have been premature on things.
After a local trip yesterday I checked the transmission fluid level and it was right at the top of safe range. I also have repeatedly checked the area where the fluid was leaking out (it literally looks like a designed vent hole) and it's as dry as a bone....not even a drop of fluid. The truck is driving and shifting fine.
Now, my concern is what might happen under a load like towing our Eagle. I do have to tow it to our local fairgrounds in a week for the county fair...however that is only a 10 mile trip. That rounds out the camping trips for this season. I think what I'm going to do is just keep an eye on it. We're taking a short trip to Madison, WI in mid-August (not taking the TT though, as it's just a few days) to visit our oldest son, so that will be a long drive (albeit without towing a TT).
Come next spring, I might look into upgrading the tranmission cooler. Right now the lines do go into the radiator. It looks like some people have switched over to the 6.0 cooler for the 7.3L. Sounds like it's a serious upgrade.
Lantley, yes this F350 is in very good shape. We had some body work done on it last year to bring it back to looking sharp. Given the price of diesel trucks these days, used or new, I plan on keeping this one a long time..especially since it's paid off. I do think if we do anything it will be to go with a remanned transmission. Can the current 4R100 in the truck be rebuilt and "toughened up" to the standards of the HD models? (not the KBS and John Woods versions, but the HD model Ford currently sells)
