Hi my car does not shift out of first gear after it warms up. The transmission shop could only find that it was not shifting into overdrive, i think they did not get the car warmed up to have the not shifting out of first. It kind of goes into neutral or no gear instead of shifting to second?
Then take it to a better transmission shop. Expect to have to replace or rebuild it.
I had that happen once, have it rebuilt with a new or rebuilt torque converter. If that’s a waste of money, then you need another car.
Rebuilding the trans on a 1997 Taurus is the definition of “waste of money”
Tom and Ray have suggested this stuff more than once