Manual Transmission Operation - GMC Sierra Classic 2007 Owner's Manual

Cruise Grade Braking is available on the 6.6L
®
DURAMAX diesel engine. Cruise Grade Braking
monitors a vehicle's cruise state, engine torque,
acceleration, vehicle speed, and the cruise set
speed. Using this information, it detects when the
truck is accelerating on a downhill grade and will
automatically downshift to slow the vehicle if it
exceeds the cruise set speed by a certain amount.
See Cruise Control on page 217 for more
information.
The Tow/Haul mode and Grade Braking shift
modes can be activated by pressing the button on
the end of the shift control stalk. If your vehicle
®
has the DURAMAX diesel Engine or the
8.1L VORTEC™ gasoline engine, Grade Braking
is only available while the Tow/Haul Mode is
selected. While in the Range Selection Mode,
Grade Braking is deactivated allowing the driver to
select a desired range of gears.
See Automatic Transmission Operation on
page 138 for more information.
Also see Towing a Trailer on page 423 for more
information.

Manual Transmission Operation

Five-Speed
(VORTEC™ 6.0L V8 Engine)
FIRST (1) is intended only for heavy loads or
trailer towing and is not recommended for
normal driving.
During the first 500 miles (805 km) of vehicle use,
start your vehicle moving in FIRST (1). This
allows clutch components to break-in properly.
Here is how to operate
your transmission.
147