My skid steer (Case 450) specs 10w30 oil for the hydraulic system (17 gallons) and drive chain oil (2 gallons each side). Given the volumes involved price is an issue. I usually just run whatever I find cheapest. Currently that's Traveler conventional at $84 per 5 gallons or ultra1plus at 77 per 5 gal blend or 86 per 5 gal full syn, all at tractor supply. I picked up some ultra1plus to try. Not sure how hydraulic use compares to engine oil use, it has a 40 gpm 3000 psi tandem gear pump so I assume shear is an issue. There is plenty of auxillary cooling and the oil runs at 160 degrees. Large full flow filtration but closed system so I would think minimal contamination except from the quick connects.