Hummer 2005 H2 - Manual (Page 176)

At approximately 265°F (130°C), the DIC 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).
If the transmission fluid reaches temperatures of
approximately 275°F (135°C) or greater, the DIC will
display a TRANS HOT IDLE ENGINE warning message
and a chime will sound. 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), please contact your
nearest dealer or the GM Roadside Assistance Center.
See Driver Information Center (DIC) on page 3-43
for further information.
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.
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 6-4 for the proper transmission maintenance
intervals.
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