95 Explorer Blinking Overdrive Light

My 95 Eddie Bauer Explorer has been to both of our local Ford dealerships in the last 9 months. One had my car for 3 days, trying to figure out this problem, the other one has had it two different times, both for 2 days. Neither one can tell me what the problem is, thus it hasn't been fixed. Once they hook up their computer to it and reset the codes, the blinking stops and they can't get it to "duplicate". It then takes approximately 3-4 weeks for it to come on again. Can anyone help me? I can't believe either of my dealerships don't have any resources they can go to for help.

Ask them to check internal operating pressure in the transmission with a gauge hooked up while driving it. Mine did this too. Low pressure condition was the cause. There was supposedly a sensor that was acting up, replaced, hasn't done it since. This was a trans shop that hosed me over badly on a rebuild, the Ford dealer actually found the problem after the trans shop kept just clearing the code and returning it to me.