I agree with MSDGN on the plain old Dex III. I had a cooling fan relay failure and cooked my Dex III to a dark red but I felt that since I have always changed it about every 25,000 miles it prevented damage to the trans.
I didn't mention it but I changed my TCC solenoid and if you have any symptoms of the trans not dis-engaging from lockup while coming to a stop or if you sense lock/unlockup happening under steady cruise, change it, its real easy to do.
One way I know of to test the TCC solenoid is under steady cruise at about 60 - 65, with steady pressure on the gas, tap the brake and watch for a slight rise in RPM and engine sound, that indicates that the TCC is working & you are dis-engaging the TCC.