Have a used 335i for last 4 weeks now and got a proceed. When I enable the Proceed i think the clutch slips under full throttle. I full throttle going about 60mph and the rpms jump about 500-750rpm and then drop down and the car accelerates? I've never seen a clutch slip for 500 or so rpms and then grip and be fine. Anyone shed some light on what is causing this? It has been a while since I have felt a cutch slip so I am not sure if it is slipping in this case or something else is going on. I am think of shooting some video of the tach if need be.