Not necessarily answering your question, but I used this in a fresh rebuilt 727: Castrol Transmax Dex/Merc

https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/2EBBCEC56A0472F5802579C3004B587E/$File/BPXE-8SL9PJ.pdf

Mainly because of this statement:
Meets DEXRON®-IIIH requirements. Also satisfies requirements of DEXRON®, DEXRON®-III, IIE and II. Do not
use this ATF in applications calling for DEXRON®-VI. Use Castrol Transmax™ Type F ATF in applications calling
for Type F.


Cant tell if it is synthetic though.