Tranny Flush, remove lower rad line or not?

[clickscrazy]

My TB was well maintained. I have records of the 100k tranny service (now has 150k).

I don't have records of the 50K, but it was probably done.

My fluid is red and looks good, but I am going to service it anyway. Especially since my recent towing experience shot my engine temp to 230 (which was probably because of the trans). Using OEM filter kit and Castrol Dextron VI (its whats available).

With that said, should I just do the standard drop pan and replace filter? or remove the lower rad line and let it pump out.

The later scares me a bit, because of the mileage on trans. I don't want to do anything to add stress to it.

[clickscrazy]

Just Update: I have decided just to drop the pan and do the filter based on my service history.