Chevrolet Express Owner's Manual page 341

3. Firmly set the parking brake.
See
.
4. Put the transmission in P (Park).
5. Secure the vehicle to the dolly
following the manufacturer's
instructions.
6. Use an adequate clamping
device designed for towing to
ensure that the front wheels are
locked into the straight position.
7. Turn the ignition to LOCK/OFF.
If the tow vehicle will not be
started or driven for six weeks or
more, remove the battery cable
from the negative terminal (post)
of the battery to prevent the
battery from draining while
towing.
The vehicle was not designed to be
towed with two wheels on the
ground. To properly tow these
vehicles, they should be placed on
a platform trailer with all four wheels
off the ground.
Towing an all-wheel-drive vehicle
with all four wheels on the
ground, or even with only two of
its wheels on the ground, will
damage drivetrain components.
Do not tow an all-wheel-drive
vehicle with any of its wheels on
the ground.