I just picked up what I think is 1946 Chevy 1.5 ton Cab & Chassis truck that is in pieces. I couldn't get the images to attach so here are google drive links to the pictures:

https://goo.gl/photos/aGjWiJaFsXKfetbY8
https://goo.gl/photos/BNWE3AMaa8FV6JYv8
https://goo.gl/photos/DE3CHZ1PtH9ENZ8z8
https://goo.gl/photos/cGMjoGz7VKRVkFoV6

I got the engine running, brakes hold a pedal, but I'm having trouble with the transmission. I can get it to go into the 4 forward gear positions(if I start to let out the clutch it will move forward in all 4 gears), The reverse lockout was frozen, I got it unstuck, but I can't get it into reverse.

Per page 48 of the 1946 GM Heritage Spec Sheet:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&sqi=2&ved=0ahUKEwjOn6iEpvzUAhUC6IMKHWtBBMcQFggkMAA&url=https%3A%2F%2Fwww.gmheritagecenter.com%2Fdocs%2Fgm-heritage-archive%2Fvehicle-information-kits%2FChevrolet-Trucks%2F1946-Chevrolet-Truck.pdf&usg=AFQjCNFVKS1O6-jkZMKn-QU8fFtfntHm9A

Reverse should be left and back. I can go left, but I can't even feel any detent to go back into.

On another note, can anyone advise visual differences in the 1941-1946 trucks? I bought this truck with a bill of sale only. The engine block number 3835794 comes back to a 42-53 216cu in block, but the ID number, KBA246257 comes back to a 1952 3100 pickup per this site:

http://chevy.oldcarmanualproject.com/models/engine.htm#41eng

There is no VIN tag on the firewall.