2007 Dodge Ram 1500 Pickup Owner's Manual - Page 332

332 STARTING AND OPERATING When operating your vehicle in 4LO, the engine speed is approximately three times that of the 2WD or 4HI 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 4 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 4 wheel drive provides improved traction, there is a tendency to exceed safe turning and stopping speeds. Do not go faster than road conditions permit. WARNING! You or others could be injured if you leave the vehicle unattended with the transfer case in the Neutral (N) position without first fully engaging the parking brake. The transfer case Neutral (N) position disengages both the front and rear driveshafts from the powertrain and will allow the vehicle to move regardless of the transmission position. The parking brake should always be applied when the driver is not in the vehicle. For additional information on the appropriate use of each transfer case mode position see the information below: 2WD Rear Wheel Drive High Range - Normal street and highway driving. Dry hard surfaced roads.