BMW Transfer case motor 27608747765

This part is a Genuine component, listed as part number 27608747765 (27-60-8-747-765) and described as Longitudinal torque module (ATC13). This motorized actuator engages the xDrive AWD system at the front differential, helping make the “xi” all wheel drive system function. 

When this part fails, the xDrive system will throw error warnings, drivetrain malfunction codes, and cause the AWD system to not properly engage. This component is a common culprit on drivetrain / AWD system problems. Fortunately it is installed externally of the transmission and differential system, and is replaceable externally make the repair not as terrible as some AWD failures on other models. 

What makes this actuator fail? 
The ATC / ATCX 13 transfer case motor is a fairly complex mechanical part with both moving parts and electronic / electrical components. It has a servo drive motor which can fail and required replacement as an assembly. It also has gears internally which can wear down or break, causing the transfer case to not properly engage / disengage. A common cause of premature transfer case actuator failure can come from running incorrectly sized or very unevenly worn tires (front to rear) which can cause the system to actuate incorrectly and do harm to this component (or worse, other components downstream). When the actuator fails, you may get error codes or issues while driving, such as jerking or shuddering while cornering or accelerating from low speeds and/or medium loads. 

Other part numbers, which may be associated related (such as previous and/or obsolete versions): 
27608747765

27108747764