Few months ago I have changed oil in manual transmission and rear axle. I used original Mercedes-Benz transmission oil #MB A001989840309 (see photo) which meets MB 235.10. And Motul Gear 300 75W90 oil in rear axle. I do not know what kind of oil was used by previous Owner of my XF but after change the oil gear shifting is far smooth and quieter. I observed that gear shifting is better with warmer transmission than shortly after start engine (especially in cold days).