Overdrive Light Flashing

Hi everyone, my wife's 2001 F-150 4X4 SuperCrew has been having an issue with the overdrive light flashing. Light on end of shift lever where you can turn OD on and off sometimes flashes and you can neither engage or disengage the OD. (off-off-off-off) Seems more prevalent when it is cold. Truck has 100,000 miles and I don't know if trans has ever been serviced. (We bought it at 90,000) Mercon V fluid and level is OK. Fluid does not smell burned nor is it discolored. Anyone have any ideas? Thanks in advance.

when I got my 98 150 it was doing the same thing,,I changed my fluid and filter that was very bad and working fine now,,good luck, ford has a lot of trans problems with all models..Hope this works for you..

If the light flashes, the computer has stored a code, get the codes read then you have a place to start. The most common cause of the OD light flashing is overheating of the ATF (too much load, too little cooling), but this does not sound likely in your case.