My overdrive stopped working?

possible problem with gearbox

im going to say your clutches are going bad

The short answer, yes. M46 models with the type J or P overdrive (depending on year and market) require a certain level of oil in the overdrive. Additionally, the overdrive is a lot like a standard automatic transmission with one gear range in theory of operation. Therefore, the hydraulic properties of said transmission do come into play here, line pressure, shifting pressure, accumulator and piston function all work together to engage or disengage the unit. Always ensure the unit is disengaged before downshifting and of course, shifting into low reverse.

Bad shift solenoid in transmissiin is my guess

For Automatic transmission problem,click the link below:----Overdrive light in the dash blinks? http://repairhelpcenter.blogspot.com/2012/01/overdrive-light-in-dash-blinks.html
--------- Automatic transmission troubleshooting:----

http://howtobyme.blogspot.com/2011/11/automatic-transmission-will-not-go-into.html

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Automatic transmission shift lever issues?-------

http://technoanswers.blogspot.com/2012/01/automatic-transmission-shift-lever-hard.html

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AUTOMATIC TRANSMISSION FLUID LEVEL? --

http://schematicsdiagram.blogspot.com/2011/07/how-to-check-automatic-transmission.html

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AUTOMATIC TRANSMISSION FLUID AND FILTER?

http://schematicsdiagram.blogspot.com/2011/07/how-to-change-automatic-transmission.html

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Transmission fault light on car dash?

http://schematicsdiagram.blogspot.com/2011/12/transmission-fault-light-on-car-dash.html

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Transmission shifting problem?

http://schematicsdiagram.blogspot.com/2012/01/transmission-shifting-problem-on-toyota.html

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Transmission Slips out of 2nd gear?

http://repairhelpcenter.blogspot.in/2012/02/transmission-slips-out-of-2nd-gear.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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Why Transmission fluid leaks near radiator?

http://repairhelpcenter.blogspot.in/2012/02/transmission-fluid-leaks-near-radiator.html

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Transmission fluid leaking?

http://technoanswers.blogspot.in/2012/02/ford-windstar-transmission-fluid.html

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****** wont go in reverse?

http://technoanswers.blogspot.in/2012/02/dodge-neon-wont-go-in-reverse.html

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Automatic transmission will not go into reverse?

http://technoanswers.blogspot.in/2012/02/dodge-automatic-transmission-will-not.html

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Transmission is making buzzing noise?

http://technoanswers.blogspot.in/2012/02/transmission-is-making-buzzing-noise.html

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This will help.

Thanks.

there is a few things the transmission fluid low or the tranmission pump is weak

You more than Likely have Broken a Tooth off of the Main Gear Inside the Transfer Case. You will need to Remove it and Inspect the Gears Very Closely. It could require a Rebuild. Please Rate My Response! Thanks!

either repair or replace the transmission...sounds like the sensor went out

Sounds like the shift kit is warn out in the transmission. The overdrive line may not be able to provide enough hydrolic pressure to engage the gears to move the truck. When you switch to regualr drive, that line is able to build the hydrolic pressure to engage the gears. At a certian speed (for the transmission, certian hydrolic pressure) there is enough pressure to engage the gears in overdrive, but go below that, and you have to start in drive again. If this is the case, there is no easy fix for that and I recomend taking it to a transmission shop to have your shift kit examined. Opening up an automatic transmission requires specalized tools, clean shop enviroment, and knowlage more then the average back yard machanic has.

The blinking overdrive button is telling u that a serious fault has occurred in the electronic controls or a mechanical fault such as excess slippage is occurring.