I just found out my 47 has a Rockwell 2 speed rear end. Do you guys know is that the axle that a COE would of came with in those years? I have heard of Eaton 2 speeds. I am pretty much a novice at these old trucks, but I had not even heard of a Rockwell before. I could not find it named in my manual, just was curious. I have a friend looking at a 53 6400 - would that be a Rockwell 2 speed also? and the correct engine a 235? Thanks for any info, Tom.