Chevrolet 2008 Express Owner's Manual page 337

CAUTION:
{
Never use oil or grease on studs or nuts.
Because the nuts might come loose. The
vehicle's wheel could fall off, causing a crash.
8. Remove any rust or dirt
from the wheel bolts,
mounting surfaces
and spare wheel.
10. Lower the vehicle by turning the jack handle
counterclockwise. Lower the jack completely.
CAUTION:
{
Wheel nuts that are not tight can work loose. If
all the nuts on a wheel come off, the wheel can
come off the vehicle, causing a crash. All
wheel nuts must be properly tightened. Follow
the rules in this section to be sure they are.
9. Put the wheel nuts
back on with the
rounded end of the
nuts toward the wheel.
Tighten each wheel
nut by hand until
the wheel is held
against the hub.
5-91