TakingThe5th wrote:
My '05 F350 6.0 also calls for a 30,000 trans oil change interval.
That seems kind of short, but a Class C 
IS pretty heavy !
I am not familiar with that transmission, but it it did nor have a drain plug from the factory, I would certainly install a magnetic drain plug the first time the job was done.  Don't worry about changing the filter.  They really are good for life of the transmission.  Even though you are not completely draining all of the fluid, I would not worry about that either.
The recommended Motorcraft ATF is either 100% synthetic or at least semi-synthetic.