the dipstick in the front, does it come out of the differential tube? or does it go back into the transmission case?
If it comes out of the differential tube then it is the fluid level for the differential fluid and you would use 90wt oil in the differential.

If the dipstick is coming from the transmission case then it is separate from the hydraulic oil and does not share the hydraulic system.
Now as far as which fluid to use?
The hydraulic system uses 10wt oil (todays equivilant is aw32).
The transmission would most likely be atf, check the dipstick, it should tell you which type fluid to use providing the stick is not corroded up and unreadable.
To be completly sure on the fluid types and weights i would refer to the specifications in the manual.

I'm going on memory on this and it's been decades since i worked on one so if you could find a manual i would do that to be honest just to make sure.