2007 Jeep Grand Cherokee Owner's Manual - Page 258

258 STARTING AND OPERATING Overdrive Operation The automatic transmission includes an electronically controlled Overdrive (5th gear for 3.7L engine, 4th and 5th gears for 4.7L and 5.7L engines). The transmission will automatically shift from direct gear to Overdrive if the following conditions are present: • the transmission selector is in D (Drive); • the engine coolant has reached normal operating temperature; • vehicle speed is above approximately 30 mph (48 km/h); • the "TOW/HAUL" button has not been activated; • transmission has reached normal operating temperature. NOTE: If the vehicle is started in extremely cold temperatures, the transmission may not shift into Overdrive and will automatically select the most desirable gear for operation at this temperature. Normal operation will resume when the transmission fluid temperature has risen to a suitable level. Refer also to the Note under torque converter clutch, later in this section. During cold temperature operation you may notice delayed upshifts depending on engine and transmission temperature. This feature improves the warm up time of the engine and transmission. If the transmission temperature gets extremely hot, the transmission will automatically select the most desirable gear for operation at this temperature. If the transmission temperature becomes hot enough, the "TRANSMISSION OVER TEMP" message may display and the transmission may downshift out of Overdrive until the transmission cools down. After cool down, the transmission will resume normal operation.