2007 Dodge Ram 1500 Pickup Owner's Manual - Page 312

312 STARTING AND OPERATING Torque Converter Clutch A feature, designed to improve fuel economy, has been included in the automatic transmission on your vehicle. A clutch within the torque converter engages automatically at calibrated speeds. This may result in a slightly different feeling or response during normal operation in the upper gears. When the vehicle speed drops or during acceleration when the transmission downshifts to second gear, the clutch automatically disengages. 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. Pressing the "TOW HAUL O/D OFF" button, when the transmission is sufficiently warm, 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 cause damage to the transmission. The torque converter will refill within five seconds of shifting from Park into any other gear position. MANUAL TRANSMISSION WARNING! You or others could be injured if you leave the vehicle unattended without having the parking brake fully applied. The parking brake should always be applied when the driver is not in the vehicle, especially on an incline.