Automatic? I have done both a 64 & 69 shortbed 1/2 tons which use the same frame as your panel I believe. 69 used a TH400, had driveshaft built locally about $125, removed carrier mount, bolts right up. On the 64, it has 700r4, I used a shaft that "came out of 85 shortbed Silverado" although it was in the bed I am not sure that's what it came out of, as engine/trans/shaft was already removed. Brian
