Something I forgot to mention. If the transmission is working as a 3 speed and does not have any unusual noises or problems the OD portion may be OK also. Many OD problems are electrical and most operators don't know how to diagnose and or fix them. It may be worth taking another look at it and adjust the price accordingly.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine