Jeep Cherokee Owner's Manual page 432

430 STARTING AND OPERATING
1-Speed 4WD Switch
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.