Most hydraulic fluids lack the friction modifiers of ATF which could lead to some very rough shifting. ATF is cheap enough to find, IMHO I would just run that.

 

Quick story...promise.
I was delivering 8 buckets of hyd oil to my uncle 40 miles in the woods, because a hose on the excavator blew. Just so happened that my 86 ranger puked all the trans fluid out at around mile 30. I had a funnel and plenty of hyd oil, and sure did t want to walk.

The transmission was never better. It immediately shifted better and smoother. It never gave me another issue for the 60k I drove it. I'd use it again in something if I had to...