Jeep 2015 Cherokee - Owner Manual - Manual (Page 480)

If the front wheels begin to lose traction, power is shifted
automatically to the rear wheels. The greater the front
wheel traction loss, the greater the power transfer to the
rear wheels.
Additionally, on dry pavement under heavy throttle
input (where one may have no wheel spin), torque will be
sent to the rear in a pre-emptive effort to improve vehicle
launch and performance characteristics.
CAUTION!
All wheels must have the same size and type tires.
Unequal tire sizes must not be used. Unequal tire
size may cause failure of the power transfer unit.
1-Speed 4X4 Switch
478 STARTING AND OPERATING