Chevrolet 2011 Express 1500 Cargo Owner's Manual page 351

4. Position the jack under the
vehicle as shown.
The front position jacking point is
on the frame. The rear position
jacking point is on the rear axle.
If the exhaust system interferes
in the jack location in the rear
axle, such as in Diesel vehicles,
place the jack (A) on the rear
axle between the axle housing
and the shock absorber
bracket in order to avoid any
interference with the exhaust
pipe (B).
Getting under a vehicle when it is
jacked up is dangerous. If the
vehicle slips off the jack you could
be badly injured or killed. Never
get under a vehicle when it is
supported only by a jack.
Raising the vehicle with the
jack improperly positioned can
damage the vehicle and even
make the vehicle fall. To help
avoid personal injury and vehicle
damage, be sure to fit the jack lift
head into the proper location
before raising the vehicle.
5. Raise the vehicle by turning the
wheel wrench clockwise. Raise
the vehicle far enough off the
ground so there is enough room
for the spare tire to fit.