The recommended torque curves for maximum durability on GM transmissions (Dexron) and Ford Transmissions (Mercon) are the same. The differences in their minimum standards lie in areas where it is easy for one fluid to cover both. The Chrysler transmissions are diffferent. You can see the graph of the torque curves one my site under "aplicaciones". You cannot have one fluid that correctly covers both. Dexron in a Chrysler transmission will cause more abrupt changes and additional wear. ATF+3 in a Dexron-designed transmission will cause slippage and wear on shifts. Their are additives that claim to change the friction characteristics, but they don't work either, as demonstrated on that graph.
Fluid characteristics for Type F are much more abrupt and damaging to both.
ATF+3 or ATF+4 should be in those transmissions. ATF+4 is supposed to be backwards compatable, but I believe that for now it is sold only by Mopar. I think it is a group III fluid, but I have not been able to confirm that. I believe the differences in performance between +3 and +4 are only in their resistance to oxidation and longer life, maintaining the same torque curves, but Chrysler wont't say. If I can ever find out I will post is as well.