93 ford e150 won't shift into 4th gear?

I have a 1993 ford e150 that I recently discovered won't shift into 4th gear. I figured it out after counting the gears when I noticed it was revving unusually high at 65mph (normal highway speed limit in my area) I checked the transmission fluid and it seemed to be at the right level. Could my transmission be going bad? It only has 147,000 miles on it. It sat in a lot for years before I bought it Any advice is appreciated.

There's a good chance your transmission is going out.

Fourth (may be) is "Overdrive". May be you have something switched off, like OD. Check your owners manual or research on line to see if your vehicle has such a feature.

The reason you might want to switch OD off is if you're going up a slight incline and your transmission is constantly shifting back and forth between drive and OD. Switching it off will put the transmission in no higher a gear than drive, and the transmission won't be doing all that crazy hard work of shifting up and down, which hurts gas mileage. But this is just a guess, I'm not the expert on this.

Hope this helps.

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There's an OD lock out button on the gear selector is it lit if it is then it won't shift into 4th gear also if there are trans issues, certain ones the OD light will blink but if there's a issue most likely your check engine light won't come on nor will the OD light blink all the time If in doubt take it to a reputable mechanic and have it checked out