'97 sable OD light blinking

I have a 1997 Sable with a Duratec 24v 3.0. The tranny shifts fine from first to second and second to third, but when i reach about 60 or 70 mph (usually when overdrive kicks in) the "Od OFF" greeen light starts blinking and the car will not shift causing the rpms to go as high as 4,000 before i slow down since it does not shift and i am affraid the tranny will go. The "service engine "light goes on sometimes, but other times it does not. I took it in to a transmission shop and was told the computer did not read anything wrong with the tranny and that it could possibly be the od solenoid or od sensor. Can anybody tell me where this sensor is located so that I can change it??

jrgarcia33023, I do not know much of anything about transmissions, but I just changed the TCC solenoid on my 98 with the AX4N transmission, and let me tell you it is a 2 man job. If your solenoid and sensor are in the same location as the TCC solenoid were good luck. I had to remove an engine mount and brace along with a bunch of other things just to get the side pan off. I hope you get some answers and it is not the same transmission and is easier to work on. Good luck