2007 Jeep Grand Cherokee Owner's Manual - Page 263

STARTING AND OPERATING 263 percent of engine torque to the rear axle. When speed differences are increased between the front and rear drive shafts, the transfer case can transmit up to 100 percent of available engine torque to the front or rear drive shafts. When additional traction is required, the 4 LOW position can be used to lock the front and rear driveshafts together and force the front and rear wheels to rotate at the same speed. The 4 LOW position is intended for loose, slippery road surfaces only. Driving in the 4 LOW position on dry hard surfaced roads may cause increased tire wear and damage to driveline components. When operating your vehicle in 4 LOW, the engine speed is approximately three times that of the 4 HI position 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 will adversely affect shifting and 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. 5