I have 2010 F150 2wd. It has 220,000 miles on the odometer. The transmission has lost overdrive, just revs up in OD, turn OD button off and it shifts fine just no overdrive (you know the drill). I dropped the pan fluid kind of off color with fine clutch material in pan, a little metal on the magnet, no chunks. Saw posts about overdrive servo snap ring. I dropped valve body and the snap ring is intact. Servo piston is in place. Is my next option a complete rebuild or can I do something without pulling transmission? The yellow plug was still in the pan

 

4 speed or 6 speed?

With 220k, I'd rebuild.

 

It is a 4 speed

 

I had this happen on my 2004 4 speed. Snap ring was in place but the ends had broken off and lodged inside the valve body preventing a valve from opening or closing. The other end of the servo piston must have come out of the overdrive band. I replaced the snap ring making sure to get the pointed end of the piston back in place, replaced all the check *****, and replaced the separator plate. Ford techmakuloco has a great video on this fix.