Fabtech 2025 GM 1500 4WD 4in Trail Boss/AT4 – Component Box 2

SKU: FTS21308 / UPC: 674866136243

Fabtech FTS21308 Component Box 2

The Fabtech Component Box 2, a key part of the complete 4-inch lift system designed exclusively for the 2025 Chevrolet Silverado 1500 4WD Trail Boss and 2025 GMC Sierra 1500 4WD AT4 models. This box delivers the rear suspension upgrades that add 4 inches of lift on top of the factory 2-inch setup, enabling clearance for 35-inch tires while preserving the original ride characteristics and load capacity. Compared to generic aftermarket options, the FTS21308 stands out with its precise engineering for these specific factory-lifted trucks, ensuring seamless integration, zero bump steer, and full steering lock without additional adjustments. Drivers report noticeable gains in ground clearance, approach angles, and overall trail capability, making it the direct path to enhanced daily and off-road driving for 2025 GM 1500 owners seeking reliable height without compromising handling or alignment.

Note: Product may vary from the image above reference only!

Vehicle Fitment Details

This component box fits only the following configurations:

• Year: 2025
• Make/Model: Chevrolet Silverado 1500 4WD Trail Boss (Crew Cab, Short Bed)
• Make/Model: GMC Sierra 1500 4WD AT4 (Crew Cab, Short Bed)
• Engine: V8 Gas
• Drive Type: 4WD

Exclusions: Does not fit models with adaptive ride control, composite rear leaf springs, or Super Cruise. Requires non-OEM wheels and tires for proper operation.

Pair this with Fabtech’s full 4-inch Basic System (kit number K1136) for complete installation, including front components in Component Box 1 (FTS21250 or equivalent for 2025) and rear performance shocks (FTS7240, quantity 2).

What’s Included in the Component Box 2 Purchase

Every FTS21308 box contains precision-machined rear suspension parts built from heavy-duty 1/4-inch steel and billet aluminum for corrosion resistance and strength under load. Here’s the full breakdown:

Part Description	Quantity	Part Number/Sub-Component	Material/Specification
Rear Lift Blocks	2	Included in FTS21308	5-inch tall steel blocks; replaces factory blocks to maintain axle alignment and payload rating
Rear U-Bolts	4	Included in FTS21308	Extended zinc-plated steel; secures rear differential to lift blocks
Rear Bump Stop Spacers	2	Included in FTS21308	Billet aluminum spacers; relocates factory closed-cell bump stops to prevent over-travel damage

These components bolt directly to factory mounting points, requiring no cutting or welding. Installation typically takes 6-8 hours with basic tools, and all hardware (bolts, nuts, washers) is provided for a straightforward rear-end upgrade.

Shipping and Packaging Specifications

• UPC: 674866136243
• SKU: FTS21308
• Shipping Weight: Not specified by manufacturer (estimated 25-30 lbs based on similar rear kits)
• Box Dimensions: 14.10 inches (width) x 13.60 inches (height) x 27.50 inches (depth)

Shipping Notes: Ships via ground freight oversized packaging may incur additional carrier fees depending on location.

The Fabtech FTS21308 Component Box 2 completes the rear of your 2025 GM 1500 4-inch lift setup, delivering the height and capability that outpaces standard spacers or blocks from other brands. Built in the USA with rigorous testing for these exact models, it supports aggressive tire sizes while keeping highway stability intact ideal for truck owners who demand fit and function tailored to their Trail Boss or AT4.

Order now to transform your 2025 Silverado 1500 or Sierra 1500 into a capable all-terrain performer.