To give another perspective to some of the comments here. I have been using and selling Amsoil synthetic oils
for over 30 years. Back in the 70s, we commonly replaced the 90 weight oils in transmissions with 20W-50 racing oil,
which has additives to prevent galling. It worked excellently in everything from VWs and BMWs, some of which are
notoriously difficult to shift into 1st while on the move (particularly when cold), to 60,000+ GVW transport trucks.
In the trucks that hauled over one particularly long adverse grade, the transmisson temperature typically was 50 degrees
lower after switching to the synthetic, and in one case, it dropped the transmission temperature 70 degrees.
Another excellent use for this oil, was in the older transmissions and transfer cases. It improved shifting dramatically.
The newer vehicles that use the ATF as the filler, can still benefit from switching to a synthetic ATF. It will run cooler,
shift better, and run quieter.
Every piece of equipment I own runs on synthetic oil including my airplane.
Bob
