Green Power Shuttle Fluid?

I replaced the fluids in a 580b. I ran it for awhile to get it up to temp and shut it off to check levels. The fresh 4 gallons of Case TCH fluid was now green. I checked the radiator and it was still full but the new 50/50 antifreeze wasn't as thin and light green. I put a few drops of the antifreeze on a piece of plastic beside a few drops of the power shuttle fluid.....they both look / feel the same. I haven't had the machine very long and don't know much of it's history but I don't think this is a new problem. When I drained the trans, the fluid had a green tint. It seems to me the only place where these could mix is in the lower tank of the radiator (where the trans fluid is cooled). Is this probable or could something else be causing it? The motor oil looks fine (no mixing). Thanks for any advise, Frank