GMC 2006 Sierra - Manual (Page 125)

Cold Weather Operation
(Allison Transmission
® )
On cold days, approximately 32°F (0°C) or colder, your
automatic transmission is designed to shift differently.
The transmission uses a warm-up mode shift schedule
until the engine reaches normal operating temperature.
While the transmission is in warm-up mode it is normal for
transmission upshifts to be delayed or held longer. This
feature improves heater performance by giving quicker
vehicle warm-ups.
When temperatures are below
−
13°F (
−
25°C), the
transmission will prevent certain operations to protect
against damage. When active the DIC will display
the message “Trans in Warm-up”.
See DIC Warnings and Messages on page 3-55 for
more information.
Tow/Haul Mode
If your vehicle has an automatic transmission, it may
have a Tow/Haul mode. If your vehicle has an
Allison Transmission
® see “Tow/Haul Mode (Allison
Transmission ® ) following. Tow/Haul mode adjusts
the transmission shift pattern to reduce shift cycling,
providing increased performance, vehicle control, and
transmission cooling when towing or hauling heavy loads.
The selector button is located on the end of the shift
lever. Turn the Turn Tow/Haul on and off by pressing
the button. When the Tow/Haul is on, a light on the
instrument panel cluster will come on.
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