The 1946 2nd series 1 ½ ton trucks did not come with a two speed rear axle. The 1939 through 1946 1st series (Interim) had a RPO two speed rear axle. So, I went and found the listing on
FB Marketplace. They have a picture of the serial number data plate. 3OS11 and it looks like 19374. 3 – St. Louis, OS-1946 Interim 1 ½ ton 160 W.B. 11-November of 45
