2001 F350, auto, P0603, O/D keeps coming on
I've searched and read several issues related to the O/D light. Here is my issue. The "O/D off" light keeps coming back on after I turn if off. I can manually shift into overdrive by pushing the button while driving, and sometimes it will stay off, but the majority of the time the O/D off light comes back on and shifts out of O/D. It is not flashing and any time. I took it to a shop and had them check for any tranny codes. The only code that came up was P0603. What do you think?