2007 GMC Yukon Owner's Manual - Page 145

Notice: Spinning the tires or holding the vehicle in one place on a hill using only the accelerator pedal may damage the transmission. If you are stuck, do not spin the tires. When stopping on a hill, use the brakes to hold the vehicle in place. When temperatures are very cold, the Hydra-Matic Automatic Transmission's gear shifting may be delayed providing more stable shifts until the engine warms up. Shifts may be more noticeable with a cold transmission. This difference in shifting is normal. The transmission torque converter clutch operation is restricted during cold operation. When the startup transmission temperature is approximately 64°F (18° C) your torque converter clutch will temporarily not operate. Once the transmission temperature rises above 68° F (20° C), normal operation will resume. Tow/Haul Mode Your vehicle has a Tow/Haul mode. The selector button is located on the end of the column shift lever. You can use this feature to assist when towing or hauling a heavy load or if there is a need to charge a battery installed in a trailer. See Towing a Trailer on page 405 for more information. 145