2011 downtown 300i oil changes , 3200 Km. ( 2000 MILES) full syn. oil, oil changes done HOT,. since new!! gear oil and engine at same time,. switched from mobil 1 5W 50 to rotela T6 5 W 40 at 50,000 Km. both seem to work fine,. in the gears I use valvaline 75/145 full Syn. on changes it looks like new oil,