2006 Dodge Ram 1500 Pickup Owner's Manual - Page 304

304 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 NOTE: The parking brake should be engaged before leaving the vehicle, especially on an incline. Truck models with manual transmission are equipped with a clutch interlocking ignition system. The clutch pedal must be fully depressed to start the vehicle. Fully depress the clutch pedal before shifting gears. As you release the clutch pedal, lightly depress the accelerator pedal.