Recently purchased a 2002 Explorer off of my so called friend. From time to time my O/D light will start flashing, esp. if I am pulling a grade, and I can tell it isnt shifting into overdrive. Other than that, it seems to shift fine. Anything Ican do to fix this, or am I looking at a rebuild?

 

THe first thing i always ask is , how old is the oil, has it been changed? Remove the pan, clean the valve, wipe off everything, change the filter... These trans are electronic shift. Small pieces of crap can cause solenoid to stick or drag.