Overdrive light flashing

i have a 1996 ford taurus dohc v6 147239 miles…when i get over 60 mph my overdrive light starts flashing and the car still drives find…i did have new transmission fluid and new fillter put in and the light was coming on before i did that and still comes on when i get over 60 mph

Possibly a faulty Vehicle Speed Sensor or problem in that circuit; usually the former.

i do have a check englen light on but it dont give a code for transmission saw it give o2 sencer

I have to back up a bit on my speed sensor comment. Your 60 MPH comment was forgotten by me and if speedometer and cruise control is working then the speed sensor is likely ok. My bad.

This may get back to overheated transmission fluid and/or a torque converter problem. The fluid was changed but that brings up the issues of how much of it was changed.
There’s also the possibility of a slipping transmission which could be overheating the fluid and if the fluid has never been changed in the prior 147k miles that’s a distinct possibility anyway.

At this point you need to have a good independent transmission shop scan the car. The CEL and O2 code would (more than likely) be unrelated.