I don't believe you ruined that tranny at all.
My wife bought TWO taurus', can't talk to her...
The first one was an '86 and the second a '92-- both had transmission issues. I believe that's why ford inevitably discontinued the model. They tried to bring it back but people ain't havin' it.
The '92 just all of the sudden disengaged and started coasting as though it were put in neutral. that was fun...
Check different years to see a pattern
http://www.carcomplaints.com/Ford/Taurus/1997/