top gear wrote:



Full synthetic oil is not snake oil. Its benefits over run of the mill
mineral oils is beyond question,

The point you are missing, is that whilst snake and full mineral oils
may well be better, are the standard and much cheaper oils GOOD ENOUGH.
Just about any modern oil - synthetic, mineral or whatever - exceeds
the sort of crap we used to chuck in a mini transaxle in the 60's, and
just about any gearbox is built to better tolerances with better a seals
and out of better materials.

All gear oil has to do is keep teh shear faces of teh gears apart under
stress. The more stress, teh more critical teh oil has to be, and teh
hiotter the box gets, teh more crirtical.

So obviously a top notch gear oil that won't break down at high temps in
say a rally car, is good news, but in boxes not under that sort of
stress, its very arguable whether it makes any difference whatsoever.

Modern teeth are much better hardened, and modern seals are much better
organised.