2006 Jeep Grand Cherokee Owner's Manual - Page 260

260 STARTING AND OPERATING 4. Wait approximately 10 seconds, then restart the engine. 5. Move the shift lever to the desired gear range. If the problem is no longer detected, the transmission will return to normal operation. If the problem persists, P (Park), R (Reverse), and N (Neutral) will continue to operate. Only Second gear range will operate in the D (Drive) shifter position. Have the transmission checked at your authorized dealer as soon as possible. Torque Converter Clutch A feature designed to improve fuel economy is included in all automatic transmissions. A clutch within the torque converter engages automatically at a calibrated speed at light throttle. It engages at higher speeds under heavier acceleration. This may result in a slightly different feeling or response during normal operation in high gear. When the vehicle speed drops below a calibrated speed, or during acceleration, the clutch automatically and smoothly disengages. The feature is operational in Overdrive and in Drive. NOTE: The torque converter clutch will not engage until the transmission fluid and engine coolant are warm [usually after 1-3 miles (1.6 - 4.8 km) of driving]. Because the engine speed is higher when the torque converter clutch is not engaged, it may seem as if the transmission is not shifting into Overdrive when cold. This is normal. Manually shifting between 3 (third gear) and 4 (fourth gear) positions (using the ERS shift control) will demonstrate that the transmission is able to shift into and out of Overdrive. NOTE: If the vehicle has not been driven in several days, the first few seconds of operation after shifting the transmission into gear may seem sluggish. This is due to the fluid partially draining from the torque converter into the transmission. This condition is normal and will not