2004 GMC Sierra 1500 Pickup Owner's Manual - Page 318

When you are back on roads, though, be sure to replace the air dam. Notice: Operating your vehicle for extended periods without the front bumper lower air dam installed can cause improper air flow to the engine and may allow things like fog lamps or tow hooks on the front of your vehicle to be damaged. Always be sure to replace the front bumper air dam when you are finished off-road driving. To reinstall the lower air dam, do the following: 1. Line up each push-pin with its intended retainer and push the washer portion of the push-pin toward the retainer until it locks into place. 2. Push the flat end of the push-pin toward the retainer until it locks into place, making sure each is secure. Before You Go Off-Roading There are some things to do before you go out. For example, be sure to have all necessary maintenance and service work done. Check to make sure all underbody shields (if so equipped) are properly attached. Be sure you read all the information about your four-wheel-drive vehicle in this manual. Is there enough fuel? Is the spare tire fully inflated? Are the fluid levels up where they should be? What are the local laws that apply to off-roading where you will be driving? If you do not know, you should check with law enforcement people in the area. Will you be on someone's private land? If so, be sure to get the necessary permission. 4-22