John Deere Hygard hydro/transmission fluid?

A neighbor had dirt contaminate the hydrostat on his powered rear axle of his 2 year old JD combine. He spent 40k replacing everything. There is a reason why the quality of the oil in hydrostats exceeds a automotive applications $$$. Different oil additive's give different wear properties as well change the foaming, friction, and heat and flash point properties.. But the reason to try JD hydro fluid is simply for the viscosity. Its thick enough that it tightens up the converter... But its thin enough that the transmission operates as normal. Now if you tried to drive it in the winter with thicker oil...its too thick and won't work right until it gets warmed up. You could easily screw it up. For a racing application I see nothing wrong with trying it. In the southern states you'll probably get by in a daily driver. Just don't visit anyone up North in the winter.