Jan/Tiger Tom,
Before you put any Gear Oil in a transmission, make sure you know
what additives are in the oil. If it is a conventional gear oil, it contains sulfur/phosphorus compounds. These additives react with yellow metals:
synchos, etc. Corrosion starts on contact and can not be stopped. Gear oil contains these extreme pressure additives plus other additives intended for final drive units. Manufacturers of heavy truck trans. still
recommend the use of motor oils unless you use a synthetic trans oil.
Coming from many years experience as a oil company rep. , I’ve
seen a lot of things tried. Stick with what the manufacturer recommends.
Bob Webb