GMC 2004 Sierra 1500 Pickup Owner's Manual page 126

THIRD (3), FOURTH (4) and FIFTH (5): Shift into
THIRD (3), FOURTH (4) and FIFTH (5) the same way
you do for SECOND (2). Slowly let up on the clutch
pedal as you press the accelerator pedal.
To stop, let up on the accelerator pedal and press the
brake pedal. Just before the vehicle stops, press
the clutch pedal and the brake pedal, and shift to
NEUTRAL.
NEUTRAL: Use this position when you start or idle
your engine.
REVERSE (R): To back up, first press down the clutch
pedal. Wait for the vehicle to stop moving and then,
shift into REVERSE (R). Let up on the clutch pedal
slowly while pressing the accelerator pedal.
Notice: Shifting to REVERSE (R) while your vehicle
is moving forward could damage the transmission.
The repairs would not be covered by your warranty.
Shift to REVERSE (R) only after your vehicle is
stopped.
Also, use REVERSE (R), along with the parking brake,
when turning off your engine and parking your
vehicle.
2-32
Six-Speed (VORTEC™ 8100 V8 and
DURAMAX™ 6600 V8 Engines)
This six-speed pattern is unique to GM manual
transmissions. The transmission always repositions the
shift lever to NEUTRAL, which is located between
FOURTH (4) and FIFTH (5) gear.
To prevent unintentional gear selections, additional
force is required to move the shift lever into
REVERSE (R) or FIRST (1). Use FIRST (1) when trailer
towing, driving with payload in the pickup box or
launching on a grade. Otherwise, start in SECOND (2)
gear. Only shift into FIRST (1) when the vehicle has
stopped moving.
Here's how to operate your
transmission.