Richard, I think so. Personally I've never refilled a jack but speaking from "more sensitive" hydraulic systems that involve pumps, motors, solenoid valves and cylinders, there have been very few made that won't run on AW-32 or DTE-24, without complaining for ~10 years of daily service.
It's closer to being ATF fluid then it is to motor oil. I always use ATF fluid to refill bottle jacks or engine hoists. I donít see why motor oil wonít work in a simple bottle jack, but why not spend the extra buck and get ATF instead.
I have used Tractor Hydraulic Fluid to refill my hydraulic jacks. It is basically a DTE-light oil with corrosion inhibitors and an anti-foam additive. I agree that ATF like "Dexron" would also be a good substitute for "hydraulic jack oil". Both Tractor Hydraulic Fluid and ATF have to operate hydraulic cylinders and work thru valves with close clearances. A neighbor was putting together a hydraulic wood splitter and needed fluid for it on a Sunday. That splitter has been running fine using Automatic Tranny Fluid from the past few years.