Chevrolet 2006 Express Van Owner's Manual page 330

Front Position
Rear Position
5-76
3. Position the jack under
the vehicle as shown.
CAUTION:
{
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.
CAUTION:
{
Raising your 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.