@oldskewel I think I understand now what you're saying. I'd hope anyone contemplating a task like changing the auto box oil would do their homework first. I have non-BMW oils in the engine and final drives, but (primarily becuase it's not possible to drain and refill completely and I wouldn't feel happy mixing them) I'd only use "BMW" oil in the gearbox, and I'd make quite sure it was the right stuff!