The invention relates to an exterior vehicle mirror having a mirror assembly mounted to a vehicle. A drive assembly comprises a drive screw coupled to a motor and a drive nut threadably mounted on the drive screw. The rotation of the drive screw by the motor causes the drive nut to traverse the drive screw. As the drive nut traverses the drive screw, it causes the extension and retraction of the mirror assembly. A slip clutch is interposed between the motor and the drive screw to enable the motor to continue to operate without damage if the mirror assembly reaches full extension or retraction.