GMC 2007 Yukon XL Owner's Manual page 414

Hitches
It's important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough
roads are a few reasons why you will need the
right hitch.
Weight-Distributing Hitches and Weight
Carrying Hitches
(A) Body to Ground Distance (B) Front of Vehicle
414
When using a weight-distributing hitch, the hitch
must be adjusted so the distance (A) remains
the same both before and after coupling the trailer
to the tow vehicle.
If you use a step-bumper hitch, the bumper could
be damaged in sharp turns. Make sure there is
ample room when turning to avoid contact between
the trailer and the bumper.
If you will be pulling a trailer that, when loaded, will
weigh more than 5,000 lbs (2 270 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 driving. Always use a sway
control if the trailer will weigh more than these
limits. You can ask a hitch dealer about sway
controls.