2005 GMC Safari Owner's Manual - Page 201

Weight-Distributing Hitches and Weight Carrying Hitches If you'll be pulling a trailer that, when loaded, will weigh more than 2,000 lbs (900 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. You should always use a sway control if your trailer will weigh more than these limits. You can ask a hitch dealer about sway controls. Will you have to make any holes in the body of your vehicle when you install a trailer hitch? If you're using the wiring provided with the factory-installed trailering package, you should not need to make any holes in the body of your vehicle. However, if you have an aftermarket hitch installed, you may need to make holes in the body. (A) Body to Ground Distance, (B) Front of Vehicle 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 to the tow vehicle. If you do, then be sure to seal the holes later when you remove the hitch. If you don't seal them, deadly carbon monoxide (CO) from your exhaust can get into your vehicle as well as dirt and water. See "Carbon Monoxide" under Engine Exhaust on page 2-26. 4-37