GMC 2010 Yukon/Yukon XL Owner's Manual page 411

If the vehicle has a two mode hybrid engine, see the
Two mode Hybrid manual for more information.
Do not tow a trailer during break in. See New Vehicle
Break-In on page 3 27 for more information.
The driver can lose control when pulling a trailer if
the correct equipment is not used or the vehicle is
not driven properly. For example, if the trailer is
too heavy, the brakes may not work well
even at all. The driver and passengers could
be seriously injured. The vehicle may also be
damaged; the resulting repairs would not be
covered by the vehicle warranty. Pull a trailer only
if all the steps in this section have been followed.
Ask your dealer for advice and information about
towing a trailer with the vehicle.
To identify the trailering capacity of the vehicle, read the
information in Weight of the Trailer that appears later
in this section.
Trailering is different than just driving the vehicle
by itself. Trailering means changes in handling,
acceleration, braking, durability and fuel economy.
Successful, safe trailering takes correct equipment,
or and it has to be used properly.
The following information has many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers. So please read this section carefully
before pulling a trailer.
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