Whats everyone using in the front axles for fluid. The manual says 80-90 or SUTD. Doesn't give any temp ranges or any other info. I live in Maine and use the tractor for snow removal. I also use the tractor in the heat of summer. The SUTD must lube the differential in the rear, because there is no other fluid back there, correct? Not looking to use the cheeper fluid, just the better for lubrication.