ReadyLIFT 4" + 2" Big Lift Kit - 2025-2026 Silverado Trail Boss / Sierra AT4 1500

The ReadyLIFT 4" + 2" Big Lift Kit (part 44-35425) is engineered for 2025-2026 Chevy Silverado 1500 Trail Boss and GMC Sierra 1500 AT4 trucks. Boxed steel crossmembers, a 3/16" plate steel skid plate, cast iron lift knuckles and Falcon rear shocks deliver the added height with ride quality that ReadyLIFT says is better than stock.

Part number: ReadyLIFT 44-35425

Key features

• 4" + 2" Big Lift for the factory-lifted Trail Boss and AT4
• Boxed steel front and rear crossmembers and a full-width 3/16" plate steel front skid plate
• 1/4" boxed plate steel differential drop brackets with double gusset and boxed center rib
• Angled and offset top mount strut extensions, plus a lower pre-load spacer that slightly raises spring rate
• Fabricated steel rear blocks with integrated bump stop landings and new Falcon rear shocks
• Includes ReadyGuard Powertrain Warranty

What's included

• Heavy-duty front and rear crossmembers and skid plate
• Heavy-duty top mount strut extensions and rear shock extensions
• Sway bar drop brackets
• Heavy-duty fabricated steel rear lift blocks with bump stop landings
• Heavy-duty cast iron lift knuckles
• Falcon rear shocks
• All necessary hardware and instructions

Fitment

• 2025-2026 Chevy Silverado 1500 Trail Boss and GMC Sierra 1500 AT4
• Not compatible with rear mono-leaf springs
• Not for diesel engines (no oil line relocation bracket included)
• Single cab configuration has not been validated by ReadyLIFT
• Use of Auto 4 Hi is not recommended

Tire fitment

• 35x12.50 on a 20x9 0 offset wheel with no trimming
• Maximum with trimming: 35x12.50 or 325/60R20 on a 20x10 -18 offset wheel; trimming covers the front valance, front and rear felt liner edges and the wheel well mud flap
• 18" wheels: only -12mm offset works; an 18x9 with 0mm or higher offset does not
• ReadyLIFT bases its wheel and tire recommendations on specific wheel and tire brands, and sizes vary by manufacturer, so test-fit every wheel and tire combination before installation.

Install notes

• Estimated installation time: 10 hours +/- 1 hour (excludes alignment and wheel/tire assembly).
• Read the instructions completely before starting. ReadyLIFT recommends installation by a certified mechanic.

Questions about fitment? Email [email protected] with your year, make, model, and trim before ordering.