The Chevrolet Trail Boss and GMC AT4 both have a factory 2" lift compared to other GM 1500 trucks of the same year model. Fabtech's suspension system for these two trucks provide a 4" lift height on top of the factory 2" lift for clearance of 35" tall tires. Once a Trail Boss or AT4 is lifted with a Fabtech 4" system, the truck will sit the same height as a 1500 with a 6" suspension and 35" tires. Fabtech's suspension design for the Trail Boss and AT4 provides excellent drive ability both on and offroad. There is zero bump steer throughout the suspension cycle that helps reduce drive fatigue while improving the overall drive ability of the vehicle. The near stock track width keeps the tires under the fenders for a clean appearance. Fabtech's proprietary steering knuckle geometry provides excellent lock to lock turning radius to maneuver in tight spots. Heavy duty 1/4" thick steel crossmembers feature OE style alignment cam pins that utilize the factory cams for easy adjustment. Triple front diff mounts reposition the differential for vibration free operation at high speed. The factory Trail Boss and AT4 coilover shocks are retained and relocated from the bottom to allow for full steer while achieving 4" of lift. Rear lift is accomplished by removing the factory 2" block and replacing it with a 5" block and u-bolt system. Fabtech has addressed all aspects of the Trail Boss suspension for proper wheel travel and lock to lock steering without over cycling. Comes with a free 5 year 60,000 mile Powertrain Warranty.