Hi, I have a 1974 F250 4x4 with a 4spd (Borg Warner T-18). I've owned this truck for 20 some years and never had any trans problems however just the other day reverse stopped working. Or I should say, I simply can't move the shifter into reverse. All of the other gears work fine. I played around with the truck for about 15mins the other day before I finally got it to go into reverse gear. I backed up for maybe fifty yards then moved forward in 2nd gear and then made a second attempt to put the truck into reverse and it was the same way. The shifter simply will not move into reverse. There's no grinding and I checked the oil level and it's full. What's the problem?

 

Probably worn shifter parts, including the stick, bushings, possibly shift forks. Parts here, and of course, there are other sources as well:

Parts for the T18 & T19 Transmissions

Not sure this is best as the kits appear to have more than you might need and I don't see the top cover parts and shifter bushings outside the kits.

Here we go, pins and inserts shown:

Borg Warner T18 Manual / Standard Transmission Parts and Diagram

As you may know, you have an access panel in the floor of your cab. You can pull the top cover off the trans to fix shifter problems.
You may only have to pull the stick and replace the pin.

Related posts:

https://www.ford-trucks.com/forums/1...18-tranny.html

https://www.ford-trucks.com/forums/6...r-removal.html

https://www.ford-trucks.com/forums/4...arner-t18.html