WARNING: This page is about a different car, the 2013 BMW 550i GT, 2012 BMW 550i GT, 2011 BMW 550i GT, and 2010 BMW 550i GT. However, it is still accessible from the selected car via links, so may be relevant.
0491521 231390 Mandrel MW
NOTE:
(Drift) For driving in the roller bearing of the countershaft in the transmission housing rear section [Discontinued]