I've always followed Fords maintenance schedule, trans filter/fluid change every 30,000 miles, and have never had a problem.
Back in 2002, sold a friend my 1995 Explorer, with 145,000 miles on it. I always followed the maintenance schedule, and they just sold it with 200,000 + miles on it, with no trans problems, and original engine. All that they did was to keep up with scheduled mainenance.