GMC 2004 Sonoma Owner's Manual page 239

Hitches
It's important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why you'll need the right hitch. Here
are some rules to follow:
•
If you use a step-bumper hitch, your bumper could
be damaged in sharp turns. Make sure you have
ample room when turning to avoid contact between
the trailer and the bumper.
•
If you'll be pulling a trailer that, when loaded, will
weigh more than 3,500 lbs. (1 589 kg) be sure to
use a properly mounted, weight-distributing
hitch and sway control of the proper size. This
equipment is very important for proper vehicle
loading and good handling when you're driving.
•
If your vehicle has the bumper delete option, do not
bolt any type of hitch to the close-out panel. The
close-out panel will not support a hitch.
Weight-Distributing Hitches and Weight
Carrying Hitches
When using a weight-distributing hitch, the hitch must
be adjusted so that the distance (A) remains the
same both before and after coupling the trailer tow
vehicle.
If you use a step-bumper hitch, your bumper could be
damaged by sharp turns. Make sure you have ample
room when turning to avoid contact between the trailer
and the bumper.
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