I have an update on my steering in my 53 3600 3/4 ton truck. The reason why my steering in my truck was so sloppy was because the king pins were frozen solid, No movement at all. The shop where I took it were able to free them up and grease them. NOW the steering has improved greatly. So don't assume it is your gearbox is the culprit.
Just an FYI.
Elmo
