OD Light blinking !?!

[pookapa]

everytime i get on the highway my overdrive light starts blinking. I dont notice any issues on the highway but when I drive around town and I come to a stop you feel it clunk out of gear right before stopping. if I park the vehicle for a little and drive around town again, the light will go off in a couple minutes, but once I get up to speed on the highway it comes back on. It happens to me twice a day (drive highway to work) it has been doing this for about a year now and its very annoying. sometimes it happens right away on the highway, sometimes it happens after driving for a while on the highway but it will always come on. any fixes? solutions? places to start looking?

 

[1998Exp]

The place to start looking is to retrieve the trouble codes from the computer. If you need help from this group, get the actual numeric code(s), post them here, and for sure someone knowledgeable about transmissions will chime in. Autozone and other auto parts stores will allegedly read trouble codes for free.

everytime i get on the highway my overdrive light starts blinking. I dont notice any issues on the highway but when I drive around town and I come to a stop you feel it clunk out of gear right before stopping. if I park the vehicle for a little and drive around town again, the light will go off in a couple minutes, but once I get up to speed on the highway it comes back on. It happens to me twice a day (drive highway to work) it has been doing this for about a year now and its very annoying. sometimes it happens right away on the highway, sometimes it happens after driving for a while on the highway but it will always come on. any fixes? solutions? places to start looking?

 

[pookapa]

I have a scanner an it doesn't trip any codes. So I'm not sure how else to check it

 

[1998Exp]

As far as I know, a blinking OD indicates that there is a transmission malfunction of some sort and a trouble code has registered.
Can your scanner read transmission codes? The simplest ones will only read 'generic' OBD2 codes, but not manufacturer specific ones. Also, if the light is not on when you scan, the code may be 'pending' -- which some simpler scanners may not be able to retrieve either.

I have a scanner an it doesn't trip any codes. So I'm not sure how else to check it

 

[Paraphoe]

A lot of times, this is a one of the warning signs before transmission failure. It was for me - blinking started, and I needed a $1500 rebuild later that year. Try having them pull the codes at Autozone if you're coming up empty.

 

[1AJeremyD]

I would most likely take it some place to get it diagnosed. A blinking light normally results in a rebuild of the transmission.

 

[carboy400]

Stop, hold up!

A blinking O/D light does NOT necessarily mean a trans failure. IF you could pookapa get me your trans model. A common problem with these vintage Ford transmissions is a TCC solenoid failure. If your skilled you can drop a pan in the junk yard and grab one the are serial numbers to stay away from though. Go to Autozone or have it scanned with a good scanner and post the code, otherwise we would be stabbing in the dark. What you are experiencing is exactly what my '99 did and many others so its possible is just a simple solenoid swap.

 

[Chris0830]

I ran into a similar problem recently driving down the Interstate. Pulled over immediately, after a bit of troubleshooting I found that the O/D switch on the gear shift had gone faulty. Resulting in intermittently shorting/opening the circuit. If you have the tools, you can verify this by taking a few panels off the steering column to find the small 2-wire harness coming from the shifter. Follow it down to wear it connects to the car wiring harness (appr 1 foot of wire). Disconnect it, drive for a while and see if the issue still remains. If it goes away, all you would need is a new shifter....which I assume would be relatively easy and cheap.

Im an aircraft electrician, but pretty novice when it comes to automobiles. Hopefully this helps, but if I'm way off base...then my apologies.

 

[drdoom]

Good replies above, also try to be observant of the vehicle behavior, particularly the torque converter lock-up at highway speeds i.e. where are your RPMs compared to normal. Be careful with this, you don't want to neglect it for too long...ask me how I know.
Best wishes.

 

[Peacock]

I have the exact same problem as the OP. It's getting progressively more frequent. A month ago, it would only happen once every couple days on the highway to and from work. Now, it's nearly guaranteed to happen if I drive on the highway for more than thirty minutes or so. It seems if I use the cruise control it takes longer to set in. I haven't noticed any difference in RPMs either. I would get it scanned, but it never happens when I'm in town near a scanner. Also, I'm starting a cross-country move on Saturday. I pray that it doesn't fail.

Any chance that a tranny flush would help? The fluid looks a little dingy but not too bad.

 

[1998Exp]

Even if the OD indicator isn't flashing at the moment, there is a good chance that a scanner will read the transmission code as 'pending'.

I have the exact same problem as the OP. It's getting progressively more frequent. A month ago, it would only happen once every couple days on the highway to and from work. Now, it's nearly guaranteed to happen if I drive on the highway for more than thirty minutes or so. It seems if I use the cruise control it takes longer to set in. I haven't noticed any difference in RPMs either. I would get it scanned, but it never happens when I'm in town near a scanner. Also, I'm starting a cross-country move on Saturday. I pray that it doesn't fail.

 

[explorerpete]

OD blinking light

What I believe you need to do is replace your Transmission Valve Body Gasket . The blinking OD light and the hard shifting of your tranny when you are slowing down to stop are very common when the gasket is torn or damaged . There is a great how to video on this web site just go to the search and type in "Replace Transmission Valve Body Gasket Video " Hope this will put an end to your problems !

 

[1AJeremyD]

I have a video of how to do a R&R on the gasket