2003 GMC Envoy Owner's Manual - Page 119

Luggage Carrier To slide the crossrails to where you want them, pull up on the lever on each side of the crossrail. This will release the crossrail and allow you to slide it. When the crossrail is where you want it, press down on the levers to lock it into place. Notice: Loading cargo that weighs more than 220 Ibs. (100 kg) on the luggage carriermay damage your vehicle. If you try to ca _r something on t . of your vehicle that is longer or wider than the luggage carrier - like paneling, plywood, a mattress and so forth - the wind can catch itas you drive along. This can cause you to lose control. What you are carrying could be violently torn off, and this could cause you or other drivers to havea collision, and of course damage your vehicle. You may be able to carry something like this inside. But, never carry something longer or wider than the luggage carrier on top of your vehicle. Don't exceed the maximum vehicle capacity when loading your vehicle. For more information on vehicle capacity and loading, see Loading Your Vehicle on page 4-48. To prevent damage or loss of cargo as you're driving, check now and then to make sure the luggage carrier is locked and cargo is still securely fastened. When the luggage carrier is not in use, place the crossrails at the following positions for wind noise reduction. Place one crossrail at the rear most point of the vehicle and the other crossrail above the opening of the rear door. A luggage carrier allows you to load things on top of your vehicle. The luggage carrier has side rails attached to the roof, sliding crossrails (if equipped) and places to use for tying things down. These let you load some other things on top of your vehicle, as long as they are not wide or longer than the luggage carrier. 2-50