33 00... Information on replacing shock absorbers: Situation
WARNING: This page is about a different car, the 2013 BMW X5 M, 2012 BMW X5 M, 2011 BMW X5 M, and 2010 BMW X5 M. However, it is still accessible from the selected car via links, so may be relevant.
When a shock absorber is faulty on one side (leaking, noises, limit values exceeded on the shock tester), often both shock absorbers on the axle in question are replaced.
E32, E34, E38, E39: With the rear spring struts with self-levelling suspension, a slight oil leak usually exists at the piston rod. These spring struts are permitted to be wet with oil over a maximum of half the shock absorber length on the outer tube, i.e. they are permitted to "sweat".