2006 GMC Yukon Owner's Manual - Page 373

Step-Bumper Pad Your vehicle has a rear step bumper with a rear step pad at the center of the bumper. If you will be using the bumper to tow a trailer, and your step-bumper has three cutout circles you must push out the center cutout circle to install the trailer ball. Trailer Recommendations You must subtract your hitch loads from the Cargo Weight Rating (CWR) for your vehicle. CWR is the maximum weight of the load your vehicle can carry. It doesn't include the weight of the people inside. But you can figure about 150 lbs. (68 kg) for each seat. The total cargo load must not be more than your vehicle's CWR. Weigh your vehicle with the trailer attached, so that you won't go over the GVWR or GAWR. If you are using a weight-distributing hitch, weigh the vehicle without the spring bars in place. You'll get the best performance if you spread out the weight of your load the right way, and if you choose the correct hitch and trailer brakes. If your step-bumper has only one cutout circle, you will have to cut out the circle, then remove it to install the trailer ball. For more information, see Towing a Trailer on page 4-60. 4-77