2001 F-150 the "OFF" light

lots of mazda vehicles have a small button on the shifter, usually on the side or somewhere not very visible. Generally overdrive is actually ON and pressing the button will turn on a light that indicates Overdrive is OFF. since overdrive is kind of a passing gear - if you are going uphill or towing something and do not want the vehicle to shift to a higher, larger gear, you would turn overdrive OFF .

Is there a button on the shifter that allows to activate or deactivate over drive? Does the OD light flash, and do you so the rpm raise at all? Nine times out of ten a over drive problem is the first symptom of the transmission in the vehicle acting up and eventually blowing.

For car not changing gears it can be shifter assembly issue, or it can also be transmission issue. Get the shifter assembly inspected with ignition OFF.

For more troubleshooting, I suggest you to get the Following help link checked, its complete step by step procedure to inspect gear shift issues: -----

GEAR SHIFT ISSUES

http://alltypesofpartsreplacing.blogspot.com/2012/11/gear-shift-issues.html

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OD light flashing and transmission fluid leaking?

http://repairhelpcenter.blogspot.in/2012/02/od-light-flashing-and-transmission.html
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These will help.
Thanks.

You can put the shifter in 2, 3, or overdrive. It will still start in first and shift up to whatever gear you have selected. Try it, you wont damage anythingl

Sounds more like a low voltage current flow in the ground circuit(harness).
Or the voltage output from ignition switch.
If No check engine light ever came on, or is not on, then the PCM/ECM is telling us there is No fault anywhere,
TCM-automatic transmission computer- uses VSS- vehicle speed sensor, to know when to shift gears.
A low input power to any of these control modules would result in lack of performance
Rough shifting could be caused by low fluid level

1. Check all fuses
2. ensure the battery cables are tight.
3. Check negative from battery has ground to frame rail
4. Check Transmission Fluid Level.

If you notice other symtoms, or situation continues, please post back

Well, if it is doing all of that, the Check Engine light has GOT to be SCREAMING at you! Continuing to try to force the vehicle to operate under such conditions will only cause further damage to the vehicle. I would recommend getting the thing to where you can scan your onboard computer and find out what is going on.

Clutches inside transmission need to be replaced
I'm

There is another recall on the cruise control. The first added a fuse. This new recall is about wiring and lighting problems caused by the cruise. Everything from not shifting out of Park to no brake lights to false dash indicators. Best to contact the dealer, if it is a recall its free.

this could mean there is a problem with the transmission,but most times when OD light is flashing it is because the wiring to the OD switch is broken.
is the OD switch on the end of the gear shift lever ?
or does your vehicle have the shifter on console between seats ?

chances are you don't have to replace the computer. the reason i tell you this is because you did not mention that the car is running lousy. no complaints of rough idle or missfire or hard starting. chances are that your engine speed sensor which sends the signal to the computer which then controls the transmission is most likely the culprit.. and it could just bhe that there is a loose connection between the two. if that is ok then your transmission control module is faulty. this is not the main computer, but the gobetween the trans and the ecm.. hope this helps please rate this...thanks(btw....the knock sensors control timing not the trans mission)