Just found this --
https://vintageautogarage.com/blog/troubleshooting-the-borg-warner-overdrive-in-a-classic-car/
"The final thing to avoid that can immediately damage the overdrive is to reverse or start in first gear while overdrive is engaged. This will instantly crush the needle bearings inside the sun gear and require a several hundred dollar repair.
Fortunately, this mistake is only possible if you bypass electrical circuits by connecting the solenoid to the overdrive toggle switch, removing the kick down switch, relay, and governor from the circuit. This is not a factory installation, but some car owners have done this over the years, and most end up later paying the repair cost as a result."