2008 GMC Envoy Owner's Manual - Page 11

Reclining Seatbacks Manual Reclining Seatbacks {CAUTION: If the seatback is not locked, it could move forward in a sudden stop or crash. That could cause injury to the person sitting there. Always push and pull on the seatback to be sure it is locked. If the seats have manual reclining seatbacks, the lever used to operate them is located on the outboard side of the seat(s). {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. 1-7