UH OH! I think your trannie is going out. a flashing OD light is always the first symptom of a dying ATX. As for clunking from 1-2... its call the 1st to 2nd bang shift, ford put a crappy shift sensor in there and it has a hard time making a good shift... I would suggest getting the part number and replaceing the shift sensor. Someone else will chime in with the part number... Who knows the new sensor may fix your OD light flashing problem.
