The rear bumper on a GMC Sierra truck is designed to protect the vehicle in the event of a collision. When a collision occurs, the bumper crumples inward, absorbing some of the impact from the crash. This bumper also contains a place to mount the rear license plate and a light to illuminate the plate in low-light and nighttime conditions. When this bumper is damaged, it cannot effectively absorb the impact from a collision and must be replaced. Replacement bumpers are available from certified GMC dealerships and automotive salvage yards.
Place the truck's transmission in park -- or first gear if it's a manual transmission -- and shut down the engine. Set the parking brake, and chock the rear wheels.
Crawl underneath the rear of the truck, and disconnect the license plate light electrical connectors from the bumper.
Remove the steel bolts that hold the bumper to the frame using a 1/2-inch ratchet connected to a metric socket.
Pull the bumper off of the truck.
