Unless the mfr says the fluid meets the requirements for both flavors, I'd stick with the Dexron in an AW4, and the 7176 or ATF+whatever in a Chrysler-built box like the ones in the Grand. There are other threads about not adding ATF+3 to a transmission running ATF+4, so I won't go into that.
Soapbox time about using synthetics in an AW4: I've used nothing but Mobil1 or Amsoil synthetic ATF in my 99 since I did the first change at 12,000. I've had no problems in 130,000 miles with synth ATF.