My overdrive i was driving my 1995 ford explorer and my overdrive light started flashing on my dash. o/d off . It doesnt feel like it is shifting into overdrive when you get going down the highway. could there maybe be a cable unplugged underneath somewhere?or could the switch go out onthe gearshifter?

Sounds like the transmission needs rebuilt

When was last time trans fluid & filter were changed? Should be done every 30k or 3years - sooner of you do any towing. Have it flushed also when doing the filter change.

When the OD light flashes in this truck it means a malfunction has occurred in the transmission, it usually will be due to excessive slippage of the transmission based on the signal of the input and output shaft speed sensors. Here is what you need to do is have the Transmission Control Module tested for the fault code or codes that was stored when the light starting flashing, it is doubtful the valve body is the problem based on my 30 years as a Ford dealer technician.

Start with simply changing filter and fluid for transmission. If that doesn,t work go to your local parts place and scan the codes on your vehicle. I have the same problem and that is what I am doing.

USUALLY WHEN YOUR OVERDRIVE LAMP IS FLASHING THAT MEANS U HAVE A PROBLEM WITH THE TRANSMISSION. YOUR EXPLORER NEEDS TO BE SCANNED AND CHECKED FOR TROUBLE CODES

You should have the computer self tested by someone with a scan tool. The flashing overdrive light indicates a concern with the transmission. Self testing the computer should produce a fault code and give you some idea of what is wrong.

This is likely your electronic speed sensor which is located under the vehicle against the frame on the passenger side.

You just go to the link I attached I'm sure you will get the solution of your problem 1998 Ford Explorer Workshop Repair Service Manual PDF Download

How many miles on car,have you every flushed the tranny?It sounds like a classic case of a stuck solinoid body,you can try flushing it if it doesnt have high miles,the fords are known for a heatation into reverse or drive when these start to get stuck.

the OD light is flashing to let u know a fault has occurred in the transmission electronic controls or that it is slipping plus other issues, go to Kragen or Autozone and ask them to run a trouble code test, it is free, post the code back here for me to look at.