It should be exactly where it shows on the manual posted above. We used to have this model. You need to be eye level with it as it shows on the manual. Standing or at an angle you probably won’t see it.
Under the cover at the top is a secondary fill port for the hydro fluid, it’s probably caked with years of mud, dirt.
Under the cover at the top is a secondary fill port for the hydro fluid, it’s probably caked with years of mud, dirt.