GMC 2013 Sierra Options Manual page 21

AUXILIARY EXTERNAL
TRANSMISSION OIL COOLER
available on sierra 1500 and
standard on sierra Hd, an air-to-oil
auxiliary cooling unit helps keep
transmission temperatures in
check—especially critical when
trailering or plowing snow.
AUTOMATIC ENGINE GRADE
BRAKING on all gas-engine sierra
models, the 6-speed transmissions
come with automatic engine Grade
Braking. This feature adds brake
assistance on downhill grades,
automatically sensing when to slow
your sierra. When the conditions are
met, it engages a Grade Braking shift
schedule that selects the right gear
to optimize engine braking.
ALLISON 1000 SERIES 6-SPEED
AUTOMATIC WITH OVERDRIVE
designed by the same company
that makes transmissions for
military tanks, this transmission
is the exclusive partner for the
available duramax diesel engine
in sierra Hd.
EATON® HEAVY-DUTY AUTOMATIC
LOCKING REAR DIFFERENTIAL no
other competitor in its class offers
an available fully automatic locking
rear differential for on- and off-road
use. available on sierra 1500 and
sierra 2500Hd and standard on
3500Hd, the eaton locker senses when
there's a difference in rotational speed
between left and right rear wheels of
approximately 100 rpm. it then locks the
differential to turn both rear wheels in
unison for added traction.
features & Benefits | 19