The Stovebolt Site Forums The Parking Lot Big Bolts Filling hydraulic hoist reservoir correctly on 2tn

Dunno that model, but if it is the big single cylender with the fill fitting on the top end you fill it with the hoist down. Filling while up will result in overflow when you lower the hoist and if the cap is installed and doesn't have a vent to release the excess fluid you may blow some seals.
Using a hand pump that screws onto a gallon jug works great for filling, there's plenty of room to work under there, just requires some reaching.

If it has a seperate resivoir you'll also want to fill it while the hoist is down. Like Dan said, if the box is up and you top off the fluid, there will be a HUGE mess when you lower the box.