How do you determine what kind of transmission is in a 97 Ford Taurus?
Check the dip stick.
Answer For fluid recommendation, refer to the Owners Manual AND the Ford Technical Service Bulletin - TSB linked below. For all model years Taurus / Sable, the TSB basically states that Mercon V is now the specified transmission fluid. See "Related Questions" below for a discussion on transmission fluids, including a Ford technical service bulletin on the topic.