2004 GMC Yukon Owner's Manual - Page 207

The following situations can cause the transmission to operate at higher temperatures: Tire Pressure Light If your vehicle is equipped with the Tire Pressure Monitor system, this light will come on if the system detects low tire pressure. Towing a trailer Hot outside air temperatures Hauling a large or heavy load Low transmission fluid level High transmission fluid level Restricted air flow to the radiator and the auxiliary transmission oil cooler (if equipped). A temporary solution to hotter transmission operating temperatures may be to let the transmission cool down. If the transmission is operated at higher temperatures on a frequent basis, see Scheduled Maintenance on page 6-5 for the proper transmission maintenance intervals. A CHECK TIRE PRESSURE DIC message will accompany the light. This light will also come on for a bulb check when the vehicle is started. See Tire Pressure Monitor System on page 5-73 for more information. For more information on the proper tire pressure, see Loading Your Vehicle on page 4-56. For more information on your tires, see Tires on page 5-64. 3-49