This part is listed by BMW as BMW part number 27107568267 and is described as Set Positioning Motor or Longitudinal Torque Module (better known as a transfer case actuator motor) for E84 X1 28iX, E70 X5 35iX/50iX, and E71 X6 35iX/50iX.
This is the servo motor which engages the xDrive AWD (All wheel drive) system's transfer case. When it fails, the xDrive system will struggle or completely fail to engage. Faults and codes are recorded, and you may hear metallic crunching/grinding noises from the teeth of the gears not making proper contact and failing to engage the rack within the transfer case.
This part is a fairly common failure on the xDrive models.
This is a xDrive servo motor manufactured by Rein Automotive - an original supplier to BMW for many systems and components on your car. As a part manufactured to OEM specs, it meets all of BMW's original design, fitment, and performance requirements and is TUV approved. OEM-type parts like Rein are the best alternative to more expensive Original BMW parts because they are virtually identical without the inflated price tag. This part has a two year warranty.
BMW Fitments:
X1 Series
E84 X1 (2013-2015) > X1 28i xDrive
E84 X1 (2013-2015) > X1 35i xDrive
X5 Series
E70 X5 (07-13) > X5 xDrive35i N55 (11-13)
E70 X5 (07-13) > X5 xDrive50i (11-13)
X6 Series
E71 X6 (2008-2014) > X6 xDrive35i N55 (10-13)
E71 X6 (2008-2014) > X6 xDrive50i (08-14)