Wow Doug I have a Roll A Car jack It looks a little newer than yours around 1940 [ Walker Roll A Car no. 764 series A ] It,s rated at 4 tons and lifts 2 feet . Lately its been getting a little week and needs it,s cyc rebuilt hope I can find some one to do it.
while you cannot mix atf and hydraulic fluid, either one will work in a hydraulic system. i work on rvs and most slide out hydraulic motors are atf. either one will work, but do not mix them