I have tried ordinary Dexron atf and it gets dark very quick
I have triend mobile 1 full synthethic , the transmission gets too smooth and more like slipping.
I mixed it with some ford ATF something like the B&M quick shift ( synthetic) and it wortks better
Recently I drained it out twice and fill it with quaker state semi synthetic ATF plus half a bottle of lucas trans fix . I have finally gained back all the quick response of the shifts and after a few months the ATF colour is still red.

 

Dexron III or better fluid always works well if the tranny fluid is powerflushed and refilled at regular intervals. 30k intervals are more than sufficent.