Tim,
My 1955 1st series GMC 1/2 ton 3-speed with torque tube has the following number on the transmission casting. C20G and 591615. Again I bought the truck in Elkhart Kansas in 1974, I assume it is the original transmission.
I still have my Dad's 51 Chevy 1 ton panel truck but it is in terrible shape. I might use the frame and engine and convert it to a I ton pick up cause I found a decent cab. Now I need to find the nine ft bed and running boards.
Good luck,
Jed
