Good general question but not a simple one to answer. So will give some background info relative to the
question.
Years ago at school a manditory course in Tribology was reguired. And later on took a company course in
lubrication which was taught by one of our company specialists.
What this dude learned was:
Didn't know how stupid I was until venturing into a discipline of a specialist discipline.
FWIW.....
Selection of a lubricant is application specific.The lubricant properties must satisfy design conditions.
(The conditions are more than just temperature or say a max viscosity). The physical characteristics of two different lubricants can seem equal at first, but just one composition difference can be rule one out over the other
( ie; compatablity with say a seal material or inertness).So the lubricant can be petrolium based / synthetic/ is in a class based on how formulated/ basic makeup/additives (ie;type/ thicknes) /viscosity, etc. Then design conditions can be max and min operating conditon/ shear rate / let us not forget cost..../oxidation stability, fire resistance / enviroment/
primary use, etc. So it an get complex quickly depending on the big picture.
So try to picture a list of all the lubricants manufactured today by all the different manufactures along with respective
applications inclusive of basic makeup and desired design conditions.
Don't know what grease is.....sorry no answer.
RICH