My daughters car is a 2002 Mazda Protege5 and at 45 mph the OD off light starts flashing and it seems to drop down a gear like I'm going to pass someone . Could this be resolved changing fluid, filter
Try taking it to a Mazda dealer or a local shop to get it checked out.
The flashing OD light means there's a problem, and its not likely going to be fixed by a fluid/filter change. It's more likely in the electronics: sensors, ecu, etc....
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