GMC Sierra 2500/3500 trucks deliver proven power and performance. Pacbrake builds them even more powerful for towing and hauling. Eliminate embarrassing truck squat, excessive bounce, bottoming out, and ride instability with Pacbrake AlphaTM HD (5,000 lb) and AlphaTM HD 7500 (7500 lb) Air Spring Suspension Kits for GMC Sierra 2500/3500 trucks. Command your ride with Wireless Air Suspension Controls. Install bigger tires on your GMC with Pacbrake anodized, all aluminum Leveling / Lift Kits. Or let 'em know you're there with Pacbrake Air Horns. GMC Sierra 2500/3500 kits by Pacbrake: Leaders of the Pack.