00 00 ... Output shafts: checking gaiters for leaks

WARNING: This page is about a different car, the 2010 BMW X3, 2009 BMW X3, 2008 BMW X3, and 2007 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.

Rotate rear left and right wheels by hand; in so doing, check inner and outer gaiters for damage such as holes, cracks or porosity
Check gaiters for leaks (emerging grease)
Check that strap retainers are securely attached to gaiters and whether any straps are missing
On all-wheel drive vehicles the same procedure applies to the output shafts on the front axle