If your transmission is picking up a fault it will go into protection mode, No OverDrive, This may just be a solonoid or perhaps something more serios like a pressure problem. Long term running in this condition will most likely cause damage, A transmission service is a small price to pay when compared with a recon or new trans.
if you have overdrive in that car it means that your about to go into overdrive
the overdrive sencer
what would transmission not to shift in to overdrive
That car is equipped with a 4R70W electronic automatic transmission through the 2005 model year, and the Overdrive OFF switch is on the end of the shift lever. Push it in to disable Overdrive, and again to re-enable Overdrive. This feature is typically only used when towing or in very hilly or mountainous terrain that would cause the transmission to "hunt" between Third and Fourth gear a lot.
Normal cause is a failed TPS. (throttle position sensor)
If the overdrive switch is turned off then the car will not go into overdrive. As it is not in overdrive, then it will not downshift out of overdrive as it normally would. It also will not shift to 3rd gear above a certain factory preset speed. Turn th overdrive on and see if it operates normally.
My 1984 corvette transmission is not shifting into overdrive. It shifts first thru third fine.
dirty trans fluid might be the cause. have it changed, but not flushd
Linkage adjust
something is wrong in the transmission. It will have to be diagnosed. You probably have a bad shift solenoid in the tranny.
it has a malfuction so its setting a code
The overdrive light to flash on 2005 Ford Expedition is caused by either the sensor problem or the electronic pressure control problem for the tranny.