2003 GMC Sierra 1500 Pickup Owner's Manual - Page 198

Tran'smission Temperature Gage At approximately 265°F (13O"C), the driver information center will display a TRANSMISSION HOT message and the transmission will enter a transmission protection mode. When the transmission enters the protection mode, you may notice a change in the transmission shifting patterns. The transmission will return to normal shifting patterns when the transmission fluid temperature falls below 260°F (127°C). See Driver Information Center (DIC) on page 3-50for further information. If your vehicle has an Allison transmission, and the fluid reaches temperatures of approximately I i center275°F (135°C) or greater, the driver information will display United States Canada a TRANS HOT IDLE ENGINE warning message and a chime will sound until the temperature falls below Your vehicle may be equipped with a transmission 265°F (129°C) degrees. Pull the vehicle off the roadway temperature gage. when it is safe to do so. Set the parking brake, place the transmission in PARK (P) and allow the engine When your ignition is on, the gage shows the to idle until the transmission temperature falls below temperature of the transmission fluid. The normal 265°F (129°C). If the transmission continues to operate operating range is from 100°F (38°C) to about above 265°F (130"C), contact your nearest dealer or 265°F (130°C). the GM Roadside Assistance Center. See Roadside Assistance Program on page 7-6. Notice: If you keep driving your vehicle with the transmission temperature gage above the normal operating range, you can damage the transmission. This could lead to costly repairs that may not be covered under your warranty. 3-43