Active Torque Coupling (ATC) Solenoid
WARNING: This page is about a different car, the 2013 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The ATC is part of the rear differential. The ATC solenoid is not repairable. If a new component is required, the ATC is installed new as an assembly with the rear axle. REFER to AXLE ASSEMBLY .