is 30 wt mineral oil the same as 30 wt motor oil? i will be using it for an e-type gearbox that has steel synchros.
Mineral oil is an older term used for engine oil that is non-synthetic. Gearbox oils usually have special additives to handle the higher forces of meshed gears. These oils often have EP in their name on the bottle. Why not check with a Jaguar parts store to make sure you buy the correct oil?
Motor oil starts with a mineral oil base, but motor oil gets other additives (as do gearbox-specific oils as wmuno indicated). Mineral oil is a very broad category (anything that is a light distillate of petroleum oil or a light synthetically-made petroleum oil) -- it is even used in cosmetics (and I wouldn't use that type of mineral oil in my gearbox ).
For a given viscosity, the SAE grade for gear and engine oil is different. See this chart from bobistheoilguy : Image Unavailable, Please Login Based on this chart I would assume that you are looking for a 85w gear oil (?), but do not take my word for granted.
