31 00... Information on replacing shock absorbers: Situation
WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 2015 BMW Alpina B7L xDrive, 2015 BMW Alpina B7 xDrive, 2015 BMW 750i xDrive, 2015 BMW 750Li xDrive, and 2015 BMW 740Li xDrive. 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, etc.), often both shock absorbers on the axle in question are replaced.