ReadyLIFT 4" Big Lift Kit 2019-2024 1500 Trail Boss / AT4 | 44-39420

ReadyLIFT 4" Big Lift Kit 2019-2024 1500 Trail Boss / AT4 | 44-39420

Overview & Application Notes

ReadyLIFT now offers an all-new 4" Big Lift Kit for the new 2019-2024 Chevy Silverado Trail Boss and GMC AT4 1500 trucks engineered for incredible ride quality and superior handling performance.  Includes ReadyGuard Powertrain Warranty.

Note:  Use of Auto 4 Hi feature not recommended. Not compatible with rear mono-leaf springs. Click here to learn how to determine if you have rear mono-leaf springs. Single Cab configuration has not been validated for fitment & drivability by ReadyLIFT.  Not for use on Diesel motor applications. 

Note:  Do not recommend an 18" wheel due to fitment issues.   A 18x9 with 0mm offset or higher does not work.

NOTE: These will not fit late model 2024 or 2025 applications that have round U-bolts. Using U-bolt part number 67-35150UB will allow this kit to fit 2025 applications.  Not for use on Diesel as we don't include an oil line relocation bracket. 

Product Details

The 44-39420 lift kit utilizes the very best in ReadyLIFT engineering with boxed steel front/rear cross members and full-width front skid plate constructed of thick 3/16" plate steel. New 1/4-inch boxed plate steel differential drop brackets feature a double gusset and boxed center rib to take the abuse of front differential torsional twisting.

Our 4" lift kit features heavy-duty angled and offset top mount strut extensions that realigns the struts to optimize shock performance and minimize wear. A specially designed lower mount strut pre-load spacer offers the added benefit of a slight increase in spring rate to better handle the larger wheels and tires that will find their way onto this new lifted truck. To lift the rear, new fabricated steel rear blocks with integrated bump stop landings have been added as well as new rear shock extensions.

With months of engineering and development and more awesome features than we could possibly mention, the bottom line is this new Big Lift Kit is the best 4" lift kit you can install on a new body style 2019-2024 GM 1500 4WD truck! Thousands of miles of road and trail testing have proven our new 4" lift kit makes these new GM 1500 trucks ride better than stock! Wheel and tire fitment information: 44-39420 6" Lift Kit - Recommended max tire with no trimming: 20x9 0 offset - 35x12.50 tire. *Max with trimming: 20x10 -18 offset - 35x12.50 or 325/60R20 *Trimming requirements for larger than recommended wheel/tire include front valance, front felt liner edge, rear felt liner edge and front-rear well edge mud flap.

NOTE: These will not fit late model 2024 or 2025 applications that have round U-bolts. Using U-bolt part number 67-35150UB will allow this kit to fit 2025 applications.  

Tire Fitment & Clearance

44-39420 4" Lift Kit - Recommended max tire with no trimming: 20x9 0 offset - 35x12.50 tire.

*Max with trimming: 20x10 -18 offset - 35x12.50 or 325/60R20

*Trimming requirements for larger than recommended wheel/tire include front valance, front felt liner edge, rear felt liner edge and front rear well edge mud flap.

Note:  If using an 18-inch only -12mm offset works.   A 18x9 with 0mm offset or higher does not work.

Wheel and tire combinations must be test-fitted. Tire construction, wheel offset and vehicle configuration can affect clearance and ride quality.

Kit Contents

Heavy-duty front-rear cross members and skid plate

Heavy-duty top mount strut extensions and rear shock extensions

Sway bar drop brackets

Heavy-duty fab steel rear lift blocks with bump stop landings.

Heavy-duty cast iron lift knuckles engineered to retain factory-quality geometry.

All necessary hardware and instructions.

Installation Instructions

• ReadyLIFT installation guide (PDF)

Warranty

ReadyLIFT’s product warranty applies to the original purchaser and covers eligible missing or defective components. Wearable components, including shocks, ball joints, heim joints, bushings and steering extensions, are covered for up to one year. Off-road abuse is excluded; Jeep SST and Terrain Flex lift kits are covered for normal recreational off-road use. Discontinued, clearance and outlet products are excluded. Labour, installation and related fees are not refundable, and consequential vehicle damage is excluded. Coverage is subject to ReadyLIFT’s full terms: ReadyLIFT warranty terms