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Overdrive light flashes on and off

About a year ago I burnt out a tranny on my 98 Protege. Every now and then the OD light would flash on and off and the revs would fluctuate wildly. One day it got so bad it just went. I got a used tranny and after a while the same thing started happening. I was told it needed a supplymental cooler so one was put in. All went fine for a number of months and it started happening again. The tranny was flushed but a few weeks later it did it again. The computer does not hold any code and the technician says we have to put the compter on it when it actually happens. As the fluid was clean and not running too hot he seems to think it may be an electrical problem. I am worried about using the car in case I burn out another tranny. Would really appreciate some suggestions. Thanks

Do you have an overdrive switch on that car? It sounds like the overdrive switch is shorting out. The same thing happened to my Windstar a few years ago. The OD wire coming up to the end of the shifter started shorting out where it makes a turn from the steering column and comes out to the end of the shifter. I peeled the rubber covering off the shifter, exposing the wire and found the bare wires right next to the sharp metal channel in the shifting lever. I wrapped slectrical tape to insulate the wires and alls well.

Do you mean the the OD light flashes once or it flashes for a time then stops? Was the cooler replaced after your first trans went out? I believe that it should have been because it might have been clogged with debris.

When the OD light flashes, it indicates a fault in the electronic controller for the transmission. Failure to repair the electronics in a timely manner will result in the need to replace mechanical parts of the transmission. If your mechanic is not aware of this, then you need a new mechanic. If you don’t believe me, then check your Owner’s Manual, which should confirm what I stated.

So, before you replace anything else in the transmission, have a competent mechanic take a look at the electronics connected with the transmission. I suggest that you seek an independent transmission shop, NOT a chain operation like Lee Myles, AAMCO, Cottman, etc.

This is something I will have looked at as I believe this is an electrical problem.
Thank you for sharing this with me.

The OD light flashes continously. If I pull over and idle for a while it will usually be okay when I resume. At the moment the tranny fluid is clean, running at normal tempreture, and I have a seperate cooler so we tend to believe the problem is electrical. Thank you for your suggestion.

I have taken 2 long rides with an inedependant tranny tech who was recommened by my regular mechanic. The tech never even charged me, he had the computer hooked up as we drove for some time but as because the problem never surfaced nothing showed. He believes it is an elerical problem but says that could be in a number of areas and we really need to have the computer diagnose exactly and it can only do that when it occurs. I appreciate your imput.