XSeries-forum

I've got a problem with the X5, the only way I can describe it is like there are leaves in the heater fan but I suspect it's something to do with the drive train. It does it at any speed but only really noticeable as your putting the car under load and accelerating. I've had the car starioanry and revved the engine and it doesn't make any noise so it's not the engine. Anyone else experienced something like this? Cheers

Yes....
Surprisingly.......

Mine was the cover cap on the transfer box output shaft seal...
If they bend or distort it can rub on the box and make a strange rubbing noise.

Mine was the front prop output shaft.