[M2M]

Originally Posted by Flyboy1st

I have worked on aircraft for about 40 years, restored old Harleys and Model A Fords, that W600 is crap. The best I have found is Mobil One synthetic 90W140. It has enough weight(thickness) to drag the gears slower for better shifting yet it is not so thick to make the roller bearings slide instead of rolling, sliding bearings due to thick oil is not good. Mobil One 140 also works good in the steering box(don't ever use grease in it). If you really need something thicker than the Mobil One, Lucas sells a nice straight 140 weight, shake the bottles and you can hear the difference.

The main problem with the oils you suggest (and the one's I suggested) is the bottle doesn't say "600W"...for many guys what's written on the bottle matters more than what the oil actually is. Also, if they purchased a quality gear oil they wouldn't be able to delve into the world of old wives' tales by adding STP, extra virgin olive oil, raw honey, etc. People spend big $ on new rear end and tranny parts and a rebuild costs then add such things rather than buy a quality gear oil !!!