Dodge Durango Owner's Manual page 302

300 STARTING AND OPERATING
WARNING!
Always engage the parking brake when powering
down the vehicle if the SVC 4WD Warning Light" is
illuminated. Not engaging the parking brake may
allow the vehicle to roll, which may cause personal
injury.
NOTE: Do not attempt to make a shift while only the
front or rear wheels are spinning. The NV 244 Generation
II transfer case is not equipped with a synchronizer and
therefore the front and rear driveshaft speeds must be
equal for the shift to take place. Shifting while only the
front or rear wheels are spinning can cause damage to the
transfer case.
When operating your vehicle in 4WD LOW, the engine
speed is approximately three times that of the 4WD or
4WD LOCK positions at a given road speed. Take care
not to overspeed the engine and do not exceed 25 mph
(40 km/h).
Proper operation of four-wheel drive vehicles depends
on tires of equal size, type and circumference on each
wheel. Any difference in tire size can cause damage to the
transfer case.
Because four-wheel drive provides improved traction,
there is a tendency to exceed safe turning and stopping
speeds. Do not go faster than road conditions permit.