4-Inch Lift Kit with M1 Struts for Trail Boss & AT4 Trucks
- Loaded M1 strut pair up front, M1 monotube shock pair at the rear
- 4 inches of lift for trucks with the 2-inch factory lift — Trail Boss and AT4 only
- Fits 2025–2026 Chevy Silverado 1500 and GMC Sierra 1500, 4WD
- Full front skid plate, high-clearance crossmember, and cast knuckles included
- Cutting and drilling required; 20-inch or larger wheels with 4.5 in backspacing
The Trail Fortress check
Will it fit your truck?
✓ Fits
✕ Does not fit
- Factory wheels
Requires cutting and drilling. ONLY fits LT Trail Boss Custom Trail Boss and AT4 models as they are equipped with a 2-inch factory lift. 20-inch or larger aftermarket wheels are required. Wheels must feature 4.5in backspacing to fit. Please test fit wheels prior to installation. Some aftermarket wheels may require 0.25" wheel spacer #1065. Fitment on this page is based on the manufacturer’s application data.
About this kit
4-Inch Lift Kit with M1 Struts, fitment-checked
M1 damping on a 4-inch lift for Trail Boss and AT4 trucks: a loaded M1 strut pair up front, an M1 monotube shock pair at the rear, and a full front skid plate, high-clearance crossmember, and cast knuckles underneath. Fits 2025–2026 Chevy Silverado 1500 LT Trail Boss and Custom Trail Boss and GMC Sierra 1500 AT4 in 4WD.
M1 hardware is what sets this build apart from the rest of the Trail Boss and AT4 lineup: the front runs a loaded M1 strut pair and the rear an M1 monotube shock pair, so the front corner arrives as a complete assembly. Structure comes from a high-clearance crossmember, full front skid plate, cast driver and passenger knuckles, and fabricated rear blocks. It works only on trucks with the 2-inch factory lift, meaning 2025–2026 Silverado 1500 LT Trail Boss and Custom Trail Boss, and Sierra 1500 AT4, in 4WD. Cutting and drilling are required.
What’s in the box
Kit contents
- 1× 6in Kit Dr Knuckle Box 21730BOX5
- 1× 6in Kit Ps Knuckle Box 21730BOX6
- 1× 6in Kit Crossmember Box 217BOX11
- 1× Universal Kit Box 110030991
- 1× FR Full Skid 217BOX3
- 1× M1 Loaded Strut Pair 502067
- 1× M1 MONOTUBE SHOCK PAIR 770739P
Rough Country shares subassemblies across kits, so individual package labels can carry broader application ranges. The complete 110340 kit fits the vehicles shown in the fitment section above.
Specifications
Specs
| Brand | Rough Country |
| Part number | 110340 |
| UPC / GTIN | 00840269966644 |
| Lift height | 4 in |
| Shock package | M1 series |
| Shipping weight | 278 lb |
| Country of origin | US |
| Category | Suspension & Lift Kits › Lift Kits |
| Installation guide | Downloadable PDF |
Why buy here