JD 7775 hydraulic or 10-30?

[Roscoe294]

I recently acquired a 1996 John Deere 7775 skid steer and have a question about the hydraulic system. Just before I got the machine, the hydraulic system was drained and fresh universal hydraulic oil and JD filter were replaced. JD calls for 10-30 to be ran thru the hydraulic system and I'm wondering if the universal hyd oil is ok? I've heard that hyd oil is too thick and may screw up the pumps in cold weather. I live in Michigan and the machine is stored cold. What do you guys use and or think?