The Stovebolt Site Forums The Shop Area Driveline Rear end identity

Hi all - I am trying to identify the rear end that is installed in my 1940 1/2 ton. It has been in the family since the 50's and I was told by a sibling that it is not the original. I have attached pics and am hoping for some help.
The numbers located on the right side (passenger) are pretty legible I feel and am confident they read as follows: 3652330. Above these digits is a 1. The left side (driver) has some letters or numbers but I have less confidence in what they read. I believe them to be 40 or A0 (A zero). I don't know what they should be, letters or numbers or combination. I am not concerned about gear ratio or anything at this point, I am just trying to pinpoint the year and is it a half ton or three quarter ton to order brake shoes, seals and the like. It is a 10 bolt and the drums are 11"

Your casting number confirms the rear came from a 1940 Chevrolet 1/2 - 1 ton truck. My books show this a a one year rear...

The casting number that looks like it's a screwed on tag is the date code, so if they used letters for the month than A = Jan, if they used numbers than 4 = Apr. The "zero" would be the year last digit which is 1940, the only zero year that used that casting part number.

Mike B