I have a 54 Dodge truck service manual. The route truck has what looks like a hollow spindle bolted to what looks a lot like a front axle (runs side to side). This axle is attached to the leaf springs. A short drive shaft is mounted to the spindle with pressed bearings and connected to the the splined centers of the rear drums. (picture a modern front wheel drive hub/axle shaft, only more primitive, but with both hub mounts attached to an axle.) The other end of the drive shaft is connected by u joints to the center section mounted by "arms" to a subframe attached to the truck frame.

If the book wasn't in such rough shape I'd scan the pictures. Its a pretty cool looking thing, but I bet it was a real pain to work on. Gene