My overdrive on/off dashboard warning light flashes after 15 to 20 minutes of driving regular highway speed. A local
Mazda dealership ran the transmission codes and told me that my transmission was overheating. They didn’t tell me what caused the overheating. They weakly suggested that I put on a new transmission cooler. Therefore I installed a new transmission cooler, nearly twice the size of the old one. This has made no difference at all.
This probelm has occurred over the last 4 years but with more frequency lately. It seems to me that if the transmission has been overheating the last 4 years, it would have been ruined by
now. I don’t think overheating is the problem. I think it could be a sensor or a wiring problem.
Usually when the light comes on, I pull over and turn off the car. I wait 20 seconds, restart the car, and the light is off. I continue to drive. I’ve experimented lately by driving the car when the light is flashing for 5 to 25 minutes. The car seems to be okay when driving with the light flashing. The only difference is, when the car shifts from first to second gear, there is a slight bump in the transmission (like a hard shift).
Does anyone have any suggestions? My car has 259,000 miles on it and this is the second transmission (it was installed about 5 years ago). I would like to drive this car 1 more year.