speed sensor or is it?
 

97 f150, 5.4 automatic, my overdrive light will suddenly begin to flash on and off and the trans will shift rather hard from gear to gear when it does. Sometimes it will do it and sometimes I can drive it for days and it won't do it at all, I can pull over when it does it shut the truck off and its good to go. Any body have any input on what the problem may be.. thanx for any ideas.