1997 ford taurus goes in reverse and goes in drive, but after going about 15 mph it pops out of gear, if I down shift manually to first gear will grab and go , but if I leave it in drive or overdrive will only go about 15-20 mph then jumps out of gear but will go back in gear at 10mph, then jumps back out of gear at 25mph?
Have changed speed sensor and fluid,@filter

Check/replace the Transmission Range (Neutral Safety) Sensor.