o/d light flashing

i have a 200 kia sephia my car has been hesitating and stalling,especially in the morning and today my o/d light starting flashing-any ideas what might be the problem?

i had the same thing happen in my 96 kia sephia rs basically u might end up needing a new tranny the gears were chewed up on mine cuz i would race it and forget to shift it oh yeah i have an automatic just take it to a tranny specialist and see what they say but make sure u trust the place just so u know u r getting a good job done