4″ Lift Kit – Front Shock Spacers & Rear Stealth Shocks – K1136M



2019-24 Chevy Silverado 1500 Trail Boss | GMC Sierra 1500 AT4 4WD

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.



1/4″ thick steel lower control arm Crossmembers are arched for maximum ground clearance. The welded box design of these Crossmembers provides additional strength to the front suspension. Retains factory alignment cams for easy adjustment.


Fabtech’s extended length ductile iron Steering Knuckles provide zero bump steer throughout the suspension travel. This provides an enhanced driver experience compared to stock. Near stock track width keeps the tires under the fenders for a clean appearance.


Oversized tie rods are provided to replace the stock units that are designed to handle oversized tires.


The factory Coilovers are relocated with heavy duty lower mounts to lift the vehicle while retaining the stock ride quality.


A heavy duty front differential Skid Plate is constructed of 1/4″ thick steel to protect the diff from offroad obstacles.


Triple Differential Mounts properly reposition the front diff for the precise CV and driveshaft angle to reduce driveline vibration at high speed.


1/4″ thick steel drop brackets reposition the front sway bar for the increased ride height. This allows the sway bar link ends to fully cycle without binding throughout the extended travel range.


Billet spacers relocate the factory closed cell bump stops to control the travel eliminating over cycling of the suspension.


5″ tall steel rear lift blocks replace the factory blocks for additional lift without changing the ride quality or load carrying capacity.


U-Bolts designed to attach the entire rear differential to the vehicle. A critical part that demands the best quality for your vehicle.


These extended length monotube shocks have a Nitrocarb piston rod for corrosion resistance and resist rock chipping. Great highway ride with good offroad damping capacity.

Part Numbers

Qty Part # Description
1 FTS21250 Component Box 1
1 FTS21251 Component Box 2
1 FTS21264 Shock Extension Kit
2 FTS6240 Rear Stealth Shock

California Prop 65 Warning

    14. Can not use OEM wheel and tire.
    79. Fits crew cab, short bed models only.
    197. Will not fit models equipped with adaptive ride control.
    262. Will not fit vehicles equipped with Super Cruise.