The big truck Columbia is mentioned in Dave Cole's article on the history of Columbia axles. The article definitely describes the axle as being an overdrive, instead of the more common underdrive two speed truck axles. This article is currently available as a pdf here:
http://www.earlyfordv8clubga.org/His...-SpeedAxle.pdf
I noticed these pictures posted by 49fordV8f4 on another forum. I asked him to post these here since there are by far more knowledgeable prewar early V8 people on the Ford Barn than I have found anywhere else. I also emailed the Columbia axle advisor for the Early V8 Club about these pictures. He replied he had never seen one of these axles, and speculated Columbia never got passed the prototype stage.
It appears to me that the red hoses visible in the axle picture are the vacuum shift hoses, supporting Dave Cole's information that the truck axle used the same controls as the cars. Does anyone else have any information on a 1 1/2 ton Columbia axle?