Your post & profile are missing vehicle specs;
my MindReading abilities are fading fast (according to my wife anyway).
Year? Engine? Auto\Manual? Transmission? 2WD\4WD?
Is OD OFF Lamp blinking?
Do all gears work 1st, 2nd, Drive, OD, Reverse?
Does it OverRev while trying to shift?
Does problem only occur forward or reverse or certain speeds?
Have you scanned OBD2 port for SAEStandard & FordProprietary TroubleCodes?
How many miles on vehicle? How many miles on Tranny?
When was Tranny ATF+Filter lasted changed?
Recent maintanence or part changes or notable events?