Most truck this is the front axel, and the line/cable attaches to an actuator that engages the gears.
Ford 150 and on up...
the ford escape you have is different....
dashboard switch on AWD models locks in a 50/50 front/rear torque split. ABS is standard on XLT versions, optional on XLS
from google...
http://consumerguideauto.howstuffworks.c...escape.htm
visit your local transmission shop