This part fits against a flat mounting face of the diff. If the casing has a spigot use PFR5-525. The flat type is pictured as A below.
Diagram Reference #25
This part fits the following models:
BMW
5 Series
E39 525i/528i/530i (1997-2003)
E39 520-530 Touring (1997-2003)
E39 540i (1997-2003)
E39 M5 (1997-2003)
E39 540 Touring (1997-2003)
7 Series
E38 7 Series (1995-2001)
Z Series
E52 Z8 (1998-2003)