2004 GMC Yukon Owner's Manual - Page 9

Front Seats Manual Seats {CAUTION: You can lose control of the vehicle if you try to adjust a manual driver's seat while the vehicle is moving. The sudden movement could startle and confuse you, or make you push a pedal when you do not want to. Adjust the driver's seat only when the vehicle is not moving. If your vehicle has a manual bucket or a split bench seat, you can adjust it with this lever located at the front of the seat. Lift the lever to unlock the seat. Using your body, slide the seat to where you want it and release the lever. Try to move the seat with your body to make sure the seat is locked into place. 1-3