Originally Posted by HFELIU
Hey Chriztofor, thanks for the right up, nice DIY. My '07 335i has 76k miles and i'm thinking about doing a transmission fluid change with castrol. Have you noticed any change in MPG?
No problem. No significant change. I think I may also try Valvoline Synthetic. I believe it is compatible (must check the spec sheet).
When you change your fluid, give us an update. So far, no one has reported transmission failure. (I don't understand how changing old, dirty, fluid is ever a bad thing.)