re: OT mechanics: 93' F-150 dies when shifted into reverse, runs fine otherwise..

Remove and clean the throttle body intake manifold that might get it fixed."

Most likely to fix trouble-easy to do and costs a little B-12/ throttle body cleaner. I do not believe it's a transmission issue. I retired form being a mechanic three yrs ago I did it for forty years. I specialized in engine performance.
Start it and listen to it idle with the hood open . See if you hear a vacuum leak by chance. Just something free to check..
I also don't know if that truck is OBD compatible-it's close to the cut-off point. If it's an EEC3 system checking codes will be different than an OBD system. Good luck.