Wont shift out of 2nd gear OD lifht flashes

Hello, the not shifting part is because the transmission is in a "fail-safe" mode to protect from safety issues and further damage. The flashing O/D light is noting a failure that requires diagnostic testing. Testing will reveal initially a diagnostic trouble code (or more than one) that will give clues as to what is going on with your Ford. Then those codes must be checked into further to get to a root cause. There are dozens of possible causes -- so no guessing possible. Here are some shops near you to consult: www.repairpal.com/repair-shops