By my tractor reference I did not mean that the tractors were chain driven. I was just describing that the drivetrain on those Macks looks like it was taken from a tractor--except chain sprockets replace the wheels.
I said the term was archaic--meaning old and out of use. It's a go kart term now. It's no good trying to apply it. I mean look at a full-floating rear axle. That, by the original use, would not be a live axle. The real axles are the little stubs on the outside of the tubes. What we call "axle shafts" are really propeller shafts because they support no weight--and do the same job the chain did.
So only a semi-float axle is a "live axle" in modern terms.
This is a go-cart wheel and is not a live axle because the axle is stationary.
This is a "live axle" hub--it's fixed to the axle, which is driven by the chain.