These are hydraulic driven pumps used to load the bulk grease in the tank on the picker. Will this type of pump pump oil or diesel fuel? Thinking about the pump and don't know if it has any type of bypass built into it. I am pretty sure when filling the pickers you shut hydraulic supply for pump off when the tank got full. The discharge hose also looks to be hydraulic hose and somewhat large than the 1/2" hoses that run the pump. Will need to look at that again.