curiousv

2000 F150 xl automatic -- can not go past 40 mph in overdrive
Overdrive button in shifter ..by default it is on but when I drive it when overdrive is on ..it wont go move than 40 mph ...if I try more than 40 mph ..engine just revs and make noise

But if I turn off overdrive by pushing that button ..it will go more than 40 mph ...but I feel it's making more noise than normally it should (may be its just in my head)

What is the reason for this ? and what is the fix?

I have been told ...changing transmission fluid with filter and adding lucas transmission fix would fix that..is that true?
Or its something inside the transmission?

frogmaster

Hello: Well that does not sound good at all. and changing the trans fluids may help if the issue is dirt or sludge or gummed up orfaces in the transmission. When you are not in overdrive the input rotational speed of the engine will be transferred to the output rotational speed and therefor a 1 in gets a 1 out, or 1 to 1.as they say. When you shift into overdrive you need to shift into play another gear so that you get more rotations out then you put into the transmission therefore overdriving the transmission output shaft. Maybe it is stuck in two gears at once and they fight each other???? Sounds to me as though some valve body or solenoid is not opening or closing properly. Possibly a good transmission flush might correct the problem, do not know.
Best of luck
Darryl...