In theory these 2 parts fit together and are welded to the outside and underside of the frame where the gearbox is mounted. I speak theory because mine didn't line up at all, but that's how I figured out the extent of the damage to my poor mangled frame. A few welds are skipped on both panels, and the lower outer edge of the frame gets a solid bead. After installation, the steering wheel became more ribbed, and the backlash almost disappeared. Happy with purchase and price.