ReadyLIFT 4.0" SST Lift Kit | 4.0" Front / 3.0" Rear | Fab Steel Offset Strut Extensions | Billet Preload Spacers | DOM Steel UCAs w/ TCT Bushings | ARC Compatible (Bracket Included) | 2019–2024 Chevy Silverado & GMC Sierra 1500 | SKU: 69-39400

Verified Fitment

Does NOT fit:

• Trail Boss, ZR2, AT4, or AT4X — factory off-road suspension trims.
• 2019 Classic body style (LD or Limited — old body).
• Super Cruise equipped vehicles.
• Single Cab — fitment and drivability not validated by ReadyLIFT.
• Mono-leaf rear spring trucks as-is — require U-bolt kit 67-39530UB (mono-leaf is identifiable by a round/circular U-bolt around the top of the leaf spring).

Additional requirements and cautions:

• Late-model 2024 and 2025 trucks with round U-bolts require U-bolt kit 67-351420UB for this kit to fit.
• Use of the Auto 4 Hi (4Auto) feature is not recommended with this kit.
• Not intended for off-road use or abuse.

Rear spring and U-bolt type are the deciding factors: Before ordering, check your rear leaf spring. Standard multi-leaf is the base fit; mono-leaf requires 67-39530UB, and round-U-bolt 2024/2025 trucks require 67-351420UB. Text (469) 407-7538 with your VIN or a photo of your rear U-bolt and we'll confirm.

Component Specifications

Offset strut extension — engineering distinction: The front lift comes from a heavy-duty laser-cut fabricated steel top-mount strut extension with an offset design that corrects the strut and wiper seal angles, working with a CNC billet aluminum preload spacer. This delivers a true 4" of front lift with improved driveline orientation over the previous 69-3940 — while staying within OEM CV tolerances rather than exceeding CV limits.

DOM steel UCAs — engineering distinction: Four inches of front lift moves the upper ball joint outside the factory arm's pivot range. The included DOM steel tubular UCAs with optimized ball joint pivot angles and maintenance-free TCT bushings restore proper suspension geometry at the new ride height — they're an essential part of the kit, not an optional add-on.

ARC compatibility built in: This kit is engineered to work with or without factory Adaptive Ride Control. The UCAs include an ARC adaptor and the kit includes an ARC Relocation Bracket, so ARC-equipped trucks retain their adaptive damping function.

Rear rake by design: The 3" cast iron rear blocks (vs. 4" front) leave a subtle factory-style rake that holds its stance under towing or payload and looks purpose-built with the GM body lines.

What Is and Is NOT Included

Critical Compatibility

New-body T1 1500 only. Fits 2019–2024 Silverado and Sierra 1500 new body. The 2019 Classic (LD/Limited old body) is excluded.

Not for off-road trims. Trail Boss, ZR2, AT4, and AT4X run different factory suspension and are not compatible.

Super Cruise excluded. Super Cruise-equipped trucks are not compatible with this kit.

Single Cab not validated. ReadyLIFT has not validated fitment and drivability on Single Cab — treat as unconfirmed.

Rear spring / U-bolt gates. Standard multi-leaf is the base fit. Mono-leaf trucks require 67-39530UB. Late-model 2024/2025 round-U-bolt trucks require 67-351420UB. These are separate purchases.

4Auto not recommended. ReadyLIFT does not recommend using the Auto 4 Hi feature with this kit.

ADAS recalibration required. GM Safety Alert Seat, Lane Keep Assist, and Forward Collision Alert must be recalibrated after install (and this kit is not for Super Cruise trucks).

Wheel & Tire Fitment

Max tire size varies by make, model year, and body style. Figures are based on Wheel Pros wheels and Nitto tires; dimensions vary by manufacturer, so every tire-and-wheel combination must be test fit before final installation.

This kit provides 4" of lift while staying within OEM CV tolerances — it does not exceed CV limits, which is part of why the tire ceiling is set where it is.

Ride quality note: Stepping up to heavier all-terrain or mud-terrain tires changes the ride. Most larger aftermarket AT/MT tires are 10-ply (Load Range E) versus a typical OEM 6-ply (Load Range C). The stiffer sidewall increases the perception of suspension stiffness often described as ride harshness, and ride, handling, traction, noise, fuel economy, and wear differ meaningfully between All-Season, All-Terrain, Mud-Terrain, and Trail-Terrain tires. Tire and wheel choice will have a real impact on how the lifted truck drives — factor it in.

Installation Notes

Skill level: Advanced — a complete no-cut bolt-on system (strut extensions, billet preload spacers, UCAs, rear cast blocks, ARC bracket). No cutting or welding, but the scope and alignment-critical UCA work make professional installation the recommended route. Estimated install time ~4.5 hours (±0.5 hr), excluding alignment and wheel/tire assembly.

Tools required: Standard hand and socket tools, torque wrench, spring compressor as needed for the strut assembly, ball joint separator. Alignment shop access required after installation.

Confirm rear spring and U-bolt type first. Verify multi-leaf vs. mono-leaf and check for round U-bolts before install — mono-leaf needs 67-39530UB and round-U-bolt 2024/2025 trucks need 67-351420UB.

Post-installation alignment is mandatory. A professional 4-wheel alignment is required to verify torque specs, confirm ride height, and lock in the corrected UCA geometry.

ADAS and headlamp recalibration. GM Safety Alert Seat, Lane Keep Assist, Forward Collision Alert, and headlamp aim must be checked and recalibrated after installation. This kit is not compatible with Super Cruise vehicles.

SAE J2492 Safety Warning: By installing this product, you acknowledge that the suspension of this vehicle has been modified. As a result, this vehicle may handle differently than factory-equipped vehicles. As with any vehicle, extreme care must be used to prevent loss of control or rollover during sharp turns or abrupt maneuvers. Always wear seat belts, and drive safely, recognizing that reduced speeds and specialized driving techniques may be required. Failure to drive this vehicle safely may result in serious injury or death. Do not drive this vehicle unless you are familiar with its unique handling characteristics and are confident of your ability to maintain control under all driving conditions. Some modifications (and combinations of modifications) are not recommended and may not be permitted in your state. Consult your owner's manual, the instructions accompanying this product, and state laws before undertaking these modifications. You are responsible for the legality and safety of the vehicle you modify using these components.

Common Questions

Does this work with Adaptive Ride Control (ARC)?
Yes — the 69-39400 is engineered to work with or without ARC. The UCAs include an ARC adaptor and the kit includes an ARC Relocation Bracket, so ARC-equipped trucks keep their adaptive damping. This is the key upgrade over the older 69-3940 it replaces.

How do I know if I have mono-leaf springs or round U-bolts?
Look at the rear leaf spring. A mono-leaf uses a round/circular U-bolt around the top of the spring — those trucks need the 67-39530UB U-bolt kit. Separately, some late 2024 and 2025 trucks use round U-bolts and need 67-351420UB. If you're unsure, text (469) 407-7538 a photo of your rear U-bolt and we'll confirm before you order.

Will it fit my Trail Boss or AT4?
No. Trail Boss, ZR2, AT4, and AT4X have different factory suspension and are excluded, along with the 2019 Classic old-body and Super Cruise trucks.

What size tire can I run?
It depends on the truck: 2019–2022 Chevy Silverado clears up to a 295/65R20 (about a 35x11.50) on a 20x9 0-offset, some trimming possible by tread; 2019–2024 GMC Sierra and 2023–2024 Chevy Silverado top out at 295/55R20 due to fender flare wheel well restrictions. Test fit your exact combo first.

Do I need an alignment afterward?
Yes — mandatory. The UCAs change camber and caster, so a professional 4-wheel alignment plus ADAS recalibration is required after install.

The Obsidian Take

The 69-39400 is ReadyLIFT's complete no-cut 4" SST system for the 2019–2024 GM 1500 — 4" of front lift on offset fabricated steel strut extensions and billet preload spacers, 3" of rear on cast iron blocks, with DOM steel UCAs and full ARC compatibility. It replaces the older 69-3940 and is the version to buy if your truck has Adaptive Ride Control, because the ARC adaptor and relocation bracket are built in.

The offset strut extension is the engineering decision that matters. A basic 4" strut spacer would push the strut and wiper seal angles out of line and steepen the CV angles; the offset design corrects the strut/wiper geometry and improves driveline orientation while deliberately staying inside OEM CV tolerances rather than exceeding them. That's why the tire ceiling is set where it is — this is a daily-drivable street lift, not an off-road-abuse kit, and ReadyLIFT says as much.

The UCAs are the other reason it rides right. Four inches of lift takes the upper ball joint past the factory arm's range; the DOM steel arms with corrected pivot angles and maintenance-free TCT bushings bring the geometry back and keep alignment in spec. Included, not optional.

The fitment traps to clear before you buy are the rear spring and U-bolt style. Multi-leaf is the base fit; mono-leaf needs the 67-39530UB kit, and round-U-bolt 2024/2025 trucks need 67-351420UB. Miss that and the rear won't bolt up correctly.

This SKU is for: 2019–2024 Silverado and Sierra 1500 owners (new body, with or without ARC) who want a complete, no-cut 4"/3" street lift with corrected UCA geometry and room for a 295-series tire, on standard multi-leaf springs — or mono-leaf/round-U-bolt trucks that add the correct U-bolt kit.

This SKU is NOT for: Trail Boss, ZR2, AT4, or AT4X trims, 2019 Classic old-body trucks, Super Cruise vehicles, unvalidated Single Cab configurations, off-road/abuse use, or anyone planning to skip the post-install alignment and ADAS recalibration.

Closing Blocks

Manufacturer Data Disclaimer
Product specifications, fitment data, and feature details are sourced from ReadyLIFT Suspension manufacturer documentation and verified third-party technical references current at the time of publication. ReadyLIFT reserves the right to modify product specifications without notice. Confirm body style (new body vs. 2019 Classic), trim, ARC status, Super Cruise status, and rear spring/U-bolt type before ordering. OFAS is not responsible for incompatibility resulting from off-road-trim misapplication, Classic-body or Super Cruise misidentification, mono-leaf or round-U-bolt spring configurations ordered without the required U-bolt kit, or failure to complete post-installation alignment and ADAS recalibration. Obsidian Forged Auto Supply is an authorized ReadyLIFT dealer.

Prop 65 Warning
⚠ WARNING: This product can expose you to chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.p65warnings.ca.gov.

Non-Returnable Notice
This item is non-returnable once installed. Verify body style, trim, ARC status, Super Cruise status, and rear spring/U-bolt type before ordering. Questions before ordering? Text (469) 407-7538.