GMC 2008 Yukon Denali Owner's Manual page 328

If you have a lot of options, equipment, passengers or
cargo in your vehicle, it will reduce the tongue weight your
vehicle can carry, which will also reduce the trailer weight
your vehicle can tow. And if you will tow a trailer, you
must add the tongue load to the GVW because your
vehicle will be carrying that weight, too. See Loading
Your Vehicle on page 4-34 for more information about
your vehicle's maximum load capacity.
The trailer tongue weight (A) should be 10 percent to
15 percent of the total loaded trailer weight (B), up to a
maximum of 600 lbs (272 kg) with a weight carrying hitch.
The trailer tongue weight (A) should be 10 to 15 percent
of the total loaded trailer weight, up to a maximum of
1,000 lbs (453 kg) with a weight distributing hitch.
4-46
Do not exceed the maximum allowable tongue weight
for your vehicle. Choose the shortest hitch extension
that will position the hitch ball closest to the vehicle. This
will help reduce the effect of trailer tongue weight on
the rear axle.
After you have loaded the trailer, weigh the trailer and
then the tongue separately, to see if the weights
are proper. If they are not, you may be able to get them
right by moving some items around in the trailer.
Trailering may be limited by the vehicle's ability to
carry tongue weight. Tongue weight cannot cause the
vehicle to exceed the GVWR (Gross Vehicle Weight
Rating) or the RGAWR (Rear Gross Axle Weight
Rating). The effect of additional weight may reduce
your trailering capacity more than the total of the
additional weight.