If its avaliabe at the same price as the usual than why not, but no real "need" to use it - the OEM spec is just fine for our tractors...

So no chance of longer service life or reduced noise (whine) then.

Doesdn't it depend on how old the airhead is and whether it has bronze anything inside it. Seem to remember that the really old ones were allergic to some modern additives.
Yes indeed, GL4 only, GL5 is a big no no.
ALL of them?Guess which goes into mine

.... <--- cooked in 100% vegetable oil, before you ask.