GMC 2003 Yukon Owner's Manual page 201

When your ignition is on, the gage shows the
temperature of the transmission fluid. The normal
operating range is from 100°F (38°C) to about
265°F (130°C).
At approximately 265°F (130°C), the message 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 3-53 for
further information.
If the transmission fluid reaches temperatures of
approximately 275°F (135°C) or greater, the Driver
Information Center will display a TRANS HOT IDLE
ENG warning message. Pull the vehicle off the roadway
when it is safe to do so. Set the parking brake, place
the transmission in PARK (P) and allow the engine
to idle until the transmission temperature falls below
260°F (127°C). If the transmission continues to operate
above 265°F (130°C), contact your nearest dealer or
the GM Roadside Assistance Center. See Roadside
Assistance Program on page 7-6 .
Notice: If you drive your vehicle with the
transmission temperature gage above normal
operating range, you can damage the transmission.
This could lead to costly repairs that would not
be covered by your warranty. Do not drive your
vehicle while the transmission temperature gage
reading is above normal. See your dealer for service.
The following situations can cause the transmission to
operate at higher temperatures:
•
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.
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