I kinda got a problem, when I got my Scag SWZ, the guy I bought it from said to use Mobil1 or Castrol synthetic 20W50 for the hydraulic fluid. When I went to AutoZone today, the guy told me that this was the wrong kind of oil to be used but he didn't know which kind would be best. It would be great if any Scag Hydro users could tell me which oil to use cause I'm confused. I've always used 20W50. That's what the guy at the dealer told me to use also.