Hummer 2010 H3 - Manual (Page 239)

Driving and Operating 9-55
To lock the rear axle, do the
following:
1. Place the transfer case in the
4LO Lock mode. This is the
only mode which will allow
the rear axle to lock. See
Four-Wheel Drive on page 9‑46
for more information regarding
the transfer case and
4LO Lock mode.
2. Press the rear axle locking
button with the vehicle moving
less than 26 km/h (16 mph).
The light in the button stops flashing
and remains illuminated when the
rear axle is locked.
Notice: If you try to lock the axle
while the vehicle is stuck and the
tires are spinning, the vehicle's
drivetrain could be damaged.
The repairs would not be covered
by the vehicle warranty. Always
lock the axle before attempting
situations and/or navigating
terrain which could possibly
cause the vehicle to become
stuck.
The locking rear axle will be
disengaged when the wheel speed
is greater than 64 km/h (40 mph),
if the vehicle's battery is low and/or
the transfer case is shifted out of
4LO Lock mode.
Notice: If the vehicle's axle
is locked while driving on
pavement, the drivetrain could be
damaged. Repairs would not be
covered by the vehicle warranty.
Do not use the locking axle on
pavement. If four-wheel drive is
needed when traveling on
pavement, use only 4HI.
Locking Front Axle
For vehicles with this feature, the
locking front axle, used with the
locking rear axle, can give the
vehicle additional traction when
traveling in off-road situations such
as mud, snow, sand, steep hills and
uneven terrain.
The button used to turn the locking
front axle on or off is located on the
instrument panel.
Before the front axle can be locked,
the rear axle must be locked.