Duane,
I towed my cobra with the wifes '97 Jimmy aproximately 400 miles when I moved from Tyler, Texas to Tulsa, Oklahoma.
It was August and over 100 degrees. I stoped about half way and checked the transmission fluid and there was nothing but bubbles on the stick.
The tranny struggled for a couple of years after that but at 59,000 miles I had to have it replaced (luckly, still under warrenty).
The Jimmy had the towing package and posessed the capacity to haul the cobra, however, it greatly shortend the life of the tranny. I'm sure the 100+ heat didn't help either.