i had a 2 speed axle in my 56 chevy school bus/camper, it was all vacuum operated
shift knob on the gear shift was cabled under the floor where the vacuum valve was located
2 loooong vacuum lines back to the vacuum actuator on the rearend for shifting
chances are if you have electric shift, it was added after 1960
i can't imagine having a hi/low knob on the dash was inducive to split shifting on hills
there is a big trucks sub-forum in this forum, you might want to ask there
most of us here have 3100 to 3800 (unless buggy has some insight)
