2000 GMC Yukon Owner's Manual - Page 161

The following situations can cause the transmission to operate at higher temperatures: D D D D D D TRANS HOT...IDLE ENGINE Your vehicle has a transmission over-temperature display contained in the message center. If this warning message is displayed, pull the vehicle off the roadway when it is safe to do so. 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" in the Index for the proper transmission maintenance intervals. Set the parking brake and place the transmission in PARK (P). Idle the engine until the message center no longer displays a message. If idling the engine does not turn the warning message off after 10 to 15 minutes, contact your nearest dealer or the GM Roadside Assistance Center. See "Roadside Assistance" in the Index. NOTICE: If you keep driving your vehicle with the transmission TRANS HOT...IDLE ENGINE message displayed, you can damage the transmission. This could lead to costly repairs that may not be covered under your warranty. 2-84