Ignoramus21579 fired this volley in
:

One of my forklift leaks. I would say, 3 ounces per night. Here is
what I know:

I couldn't tell you what Hyster uses for that model (or even the model,
since you didn't include it).

HOWEVER, a lot of hydraulic implements use common Type-F Automatic
Transmission Fluid as the hydraulic oil.
(some use common motor oil, too. There are actually a few that use
'real' hydraulic fluid, proper.)

Have you ever checked the color of the oil in the "fill here" port?

LLoyd