ReadyLIFT 2.25-Inch Forged Torsion Key Leveling Kit with Extreme-Duty UCAs | 4130 Chromoly Arms | 1-Ton Ball Joints | TCT Bushings | Shock Extensions Included | 33" Tire Clearance | 2011–2019 Chevy Silverado / GMC Sierra 2500HD / 3500HD | SKU: 66-3012

Verified Fitment

Does NOT fit:

• 2020 and newer Chevy Silverado / GMC Sierra 2500HD / 3500HD — GM revised the HD torsion bar suspension design for the 2020 generation; order ReadyLIFT 69-30300 for 2020–2026 HD applications
• 2010 and earlier GM HD 2500/3500 — previous-generation platform uses different torsion key dimensions
• Chevy Silverado / GMC Sierra 1500 — different front suspension architecture

Fender measurement limits — must verify before setting torsion preload:

• 4WD trucks: Lift height must not exceed 26.25 inches measured from the wheel center to the fender lip at the 12 o'clock position
• 2WD trucks: Lift height must not exceed 27 inches measured from the wheel center to the fender lip at the 12 o'clock position

These measurements are the hard upper limits set by ReadyLIFT for the 2011–2019 HD platform to maintain proper CV angles and suspension travel. Measure after installation — adjust torsion preload downward if either measurement exceeds the limit for your drivetrain.

Component Specifications

Torsion Key System (66-3011 components):

44-3100 Extreme-Duty Upper Control Arms:

Why this kit over the 66-3011 alone: The 66-3011 torsion key kit raises the front of the truck and includes shock extensions to preserve factory ride quality. What it doesn't replace is the factory upper control arm — which at 2.25 inches of torsion key lift operates at a different ball joint angle than it was designed for. The factory UCA geometry was engineered for stock ride height. At 2.25 inches of torsion key preload, the factory UCA ball joint operates at an off-angle position, which over time produces accelerated ball joint wear and steering geometry deviation — especially under the additional stress of heavy aftermarket wheels and 33-inch tires. The 44-3100 UCAs correct ball joint angle to the lifted position, solving the geometry problem the factory arm leaves unsolved.

4130 chromoly vs. mild steel UCAs: 4130 chromoly is a chromium-molybdenum alloy steel that provides a superior strength-to-weight ratio compared to mild steel. At .125" wall thickness in the tab-and-slot boxed construction, the 44-3100 creates a structural arm capable of handling the forces of 1-ton ball joints and heavy wheel loads without the weight penalty of thicker mild steel construction.

TCT bushing "side biter" washers: The proprietary free-floating bushing design uses side biter washers that create a mild preload on the bushing's outer face — this mild preload helps maintain the bushing's lateral position during alignment and prevents the drift that can occur with conventional floating bushings over time.

What Is and Is NOT Included

Critical Compatibility

Same year range restrictions as 66-3011 — 2011–2019 HD only. The torsion keys are dimensioned for the 2011–2019 HD suspension architecture. The 44-3100 UCAs are also dimensioned for the same 2011–2019 upper control arm mounting geometry. Both components require the 2011–2019 platform — 2020+ or pre-2011 trucks are not compatible.

Fender measurement is the operational lift limit — not just 2.25 inches. On 4WD trucks, 26.25 inches from wheel center to fender lip is the absolute maximum. On 2WD trucks, 27 inches is the limit. Many owners of 2011–2019 HD trucks find that the factory ride height is already relatively close to these measurements depending on trim and load configuration. Measure your factory ride height before installing and calculate the maximum additional torsion preload before it reaches the fender measurement limit.

UCA lift range (0"–8") is separate from the torsion key range (0"–2.25"). The 44-3100 UCAs are engineered for 0–8 inches of front lift. If this truck later receives a full lift kit beyond torsion key adjustment (e.g., a coilover conversion or a different front lift approach), the 44-3100 UCAs remain compatible through that full range. They are not limited to the 2.25" torsion key application.

Installation Notes

Skill level: Intermediate to advanced — torsion key swap plus UCA replacement on a heavy-duty platform. Two distinct installation tasks. Professional installation recommended.

Mandatory tool — ReadyLIFT Universal Torsion Key Unloading Tool: Same requirement as the 66-3011. Not included. Must be sourced before installation begins.

Installation sequence — two-phase:

Phase 1 — UCA installation:

1. Safely lift and support the vehicle with front suspension at full droop.
2. Remove factory upper control arms.
3. Install 44-3100 Extreme-Duty UCAs using Grade 8 hardware — bolt-on, no modifications required.
4. Confirm TCT bushing and side-biter washer seating per ReadyLIFT instructions.
5. Install billet aluminum ball joint cap.

Phase 2 — Torsion key leveling:

1. Use the ReadyLIFT Universal Torsion Key Unloading Tool to fully relieve torsion bar preload.
2. Remove factory torsion keys.
3. Install ReadyLIFT forged torsion keys — confirm wider keyway shoulder seats correctly.
4. Install shock extension spacers at front shock mounting locations using new shock mounting nuts.
5. Set torsion preload to desired ride height — do not exceed 2.25 inches.
6. Lower vehicle and verify ride height.
7. Measure from wheel center to fender lip: 4WD must not exceed 26.25"; 2WD must not exceed 27". Adjust if needed.

Post-installation mandatory steps:

1. Professional 4-wheel alignment — mandatory; both UCA installation and torsion key preload change affect caster, camber, and toe.
2. Headlamp aim adjustment — required.
3. ADAS verification — check and adjust all GM safety systems.
4. Test fit tires — verify at full articulation and full steering lock before mounting.

Common Questions

What does this kit include compared to the 66-3011?
The 66-3012 is the 66-3011 torsion key leveling kit (forged torsion keys + shock extensions + shock mounting nuts) bundled with the ReadyLIFT 44-3100 Extreme-Duty Upper Control Arms. The 66-3011 alone raises the front and preserves factory ride quality but leaves the factory UCAs in place — operating at off-angle ball joint geometry at the new ride height. The 44-3100 UCAs correct ball joint pivot angle to the leveled position, providing complete geometry correction that the torsion keys alone cannot deliver.

Why replace the UCAs if the torsion key kit alone levels the truck?
The factory UCAs were designed for stock ride height geometry. At 2.25 inches of torsion key preload, the factory ball joint operates at an angle outside its designed range. Under the additional load of heavy aftermarket wheels and 33-inch tires, that off-angle operation accelerates ball joint wear. The 44-3100 UCAs correct this — the 1-ton spring-loaded HD ball joint operates at the correct angle for the lifted position, dramatically extending joint life and maintaining proper steering geometry.

What is the fender measurement limit and why does it matter?
ReadyLIFT specifies that 4WD trucks must not exceed 26.25 inches from wheel center to fender lip, and 2WD trucks must not exceed 27 inches. Exceeding these measurements overlifts the front — the CV axles operate outside their designed angle range, and the suspension runs out of droop travel. The result is CV wear, poor ride quality, and potential CV failure. Measure before and after setting torsion preload to confirm you're within the limit.

Can the 44-3100 UCAs be used with a full lift kit later?
Yes — the 44-3100 UCAs are confirmed for 0–8 inches of front lift. If this truck later receives a larger front lift beyond torsion key adjustment, the UCAs remain compatible through that full range.

Do I need the torsion key unloading tool?
Yes — same requirement as the 66-3011. The torsion bar stores significant energy under preload. Removing keys without the proper unloading tool is a serious safety hazard. Source the ReadyLIFT Universal Torsion Key Unloading Tool before scheduling installation.

The Obsidian Take

The 66-3012 is the complete leveling solution for the 2011–2019 HD — not just the height change, but the geometry correction that makes the height change work correctly for the life of the truck.

The 66-3011 torsion key kit raises the front, includes shock extensions, and preserves factory ride quality. What the 66-3011 doesn't address is the factory upper control arm operating at an off-angle ball joint position at the new ride height. Under a stock wheel and tire package, that off-angle operation is a minor long-term concern. Under a 33-inch tire on a 9-inch wheel — which is the tire package most owners are installing alongside this leveling kit — the additional weight and leverage on the ball joint amplifies that wear rate significantly.

The 44-3100 UCAs solve this. The 4130 chromoly tab-and-slot boxed construction, the 1-ton spring-loaded ball joint at the corrected pivot angle, the TCT bushing with side-biter washers, the billet aluminum protection cap — these are components designed for the load environment of a 2500/3500 HD running large tires. The geometry is right. The material is right. The protection from debris that destroys conventional ball joints is right.

The fender measurement limits are the one installation detail that catches owners off guard. The 26.25" (4WD) and 27" (2WD) limits from wheel center to fender lip are the operating ceiling — measure after installation, before the truck comes down from the alignment lift.

This SKU is for: 2011–2019 Chevy Silverado and GMC Sierra 2500HD and 3500HD owners (2WD and 4WD) who want the complete front leveling solution — forged torsion keys, shock extensions, and geometry-corrected Extreme-Duty UCAs with 1-ton ball joints — for a level stance, 33-inch tire clearance, and long-term suspension durability under heavy wheel and tire loads.

This SKU is NOT for: 2020 and newer HD owners (order 69-30300), pre-2011 HD owners (different platform), Silverado/Sierra 1500 owners, anyone who hasn't sourced the torsion key unloading tool before installation, or anyone who needs only the torsion key kit without UCA upgrade (order 66-3011 instead).

SAE J2492 Warning
⚠ 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.

Manufacturer Data Disclaimer
Product specifications, fitment data, and feature details are sourced from ReadyLIFT 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 2011–2019 model year, HD 2500/3500 configuration, fender measurement limits (4WD: 26.25" / 2WD: 27"), and torsion bar unloading tool availability before ordering. OFAS is not responsible for incompatibility resulting from 2020+ generation applications, pre-2011 applications, fender measurement exceedance, or installation without proper torsion bar unloading equipment.

Prop 65 Warning
⚠ WARNING: This product can expose you to chemicals including lead and lead compounds, which are 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 2011–2019 model year, HD configuration, and fender measurement limits before ordering. Questions before ordering? Text (469) 407-7538.