I thought I saw a chain drive, I guess that's the spring shackle and a bracket or something ahead of that. Maybe it's that W series of the early thirties? Enclosed cab and pneumatic tires would put it in the late 20s or early 30s.
Enclosed is a picture of an A7 with a double reduction IH axle and leaf springs on top and bottom of the axle. I have pictures of the W model from the 1920s but can't find them right now.
Great pictures and a California trailer.