I have a 2011 x5 diesel. On 5 occasions, while going <10 mph, the engine dies and the transmission goes into neutral. I have had the X5 checked twice about this and nothing could be found. In fact, no warning or code displays on my screen or on the dealer's scan. The most recent time was today. I was going along a gravel driveway at 5 mph or so when it quit. Putting it into park and restarting is always successful. There is no loss of electrical power. There seems to never be any engine issues at speed. Any ideas about the problem?