Here are a couple of screen shots from pertinent resource books that tell you exactly where to find your '56 3100 rear axle code/serial number along with the info to decode to know what you have.

The code/serial number is "stamped" into the face on the front axle pumpkin surface (left edge if you are facing towards the rear of the truck). The other "raised" numbers and symbols are part number and casting date code info that help define when it was manufactured.

Probably going to need to hit that surface with a stiff wire brush to clean off any road grime/oily residue to expose the stamping.

Hope you are able to use this info to confirm your info before ordering.

Dan
Attachments
Rear axle code and serial number data 1956-Chevrolet-Truck.pdf.png (231.21 KB, 91 downloads)
Rear axle general data
Pic displaying location of 3100 rear axle code and serial number 1955 Chevy Truck 2nd Series Shop Manual.png (221.02 KB, 91 downloads)
Actual code/serial number stamping location

Last edited by Gdads51; 04/12/2023 4:16 PM.
~ Dan
1951 Chevy 3 window 3100
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