morning folks

i'm having some seals made for an Eaton pump and the man is asking what fluid is being used,mineral base or esters???

i googled it and the nearest i could come up with was synthetic oil!

i think Nitrile is the correct material but it does not perform so well with esters whatever they are.

so is ATF/power steering fluid mineral or ester based?

hope there is an expert out there

many thanks

stuey