JKS JSPEC166KFA 2.5in J-Kontrol FOX Diesel 392 Lift Kit Jeep Wrangler JL 4-Door

Vehicle Fitment

• 2020-2026 Jeep Wrangler JL Unlimited 4-Door with 3.0L EcoDiesel V6 engine, 4WD
• 2021-2026 Jeep Wrangler JL Unlimited Rubicon 392 with 6.4L V8 engine, 4WD

Fitment Notes

• Diesel and Rubicon 392 engines only - for gas-engine (3.6L/2.0T) JL 4-Door J-Kontrol 2.5" see JSPEC137KFA
• 4-Door (Unlimited JL) only
• Does not fit 2021-2026 Jeep Wrangler JL 4xe (plug-in hybrid) models
• Uses Diesel-specific 2.5" coil springs (JSPEC1252 front, JSPEC1259 rear) - distinct from gas-engine kits and not interchangeable with 3.5" Diesel lift springs
• Factory wheels cannot be reinstalled without wheel spacers after lift
• Maximum recommended tire size: 35x12.50 (Sport/Sahara/Willys); 37x12.50 (Rubicon with 5" backspacing)

Features

• Diesel-specific JSPEC dual-rate front and rear coil springs (JSPEC1252/JSPEC1259) tuned for the EcoDiesel V6 and 6.4L V8 front-end weight at 2.5" lift
• Custom-valved FOX 2.0 Adventure Series IFP monotube gas shocks matched to this Diesel/392 JL J-Kontrol 2.5" system
• Front Control Arm Correction Brackets (heavy-duty, fully boxed 7GA steel - JKS6201) flatten upper and lower control arm angles to correct caster and mimic factory suspension geometry at lifted height
• Retains OE control arms - no replacement arms required
• JKS front adjustable track bar and rear track bar bracket correct axle positioning at lifted ride height
• JKS2033 Quicker Disconnect front sway bar links unlock up to 30% more front axle articulation on the trail
• Rear extended sway bar links correct operating angle and improve strength at lifted height
• Front and rear bump stop extensions properly limit suspension up-travel at lifted height

Specifications

• Lift Height: 2.5 inches
• Platform: Jeep Wrangler JL Unlimited 4-Door - EcoDiesel V6 and Rubicon 392 V8
• System Level: J-Kontrol (step above J-Venture - adds Front Control Arm Correction Brackets)
• Shock Series: FOX 2.0 Adventure Series IFP (custom-valved for this system)
• Control Arm: OE arms retained; geometry corrected via fully boxed 7GA steel correction brackets (JKS6201)
• Front Spring: JSPEC1252 (Diesel/392 specific 2.5" front)
• Rear Spring: JSPEC1259 (Diesel/392 specific 2.5" rear)
• Max Recommended Tire Size: 35x12.50 (Sport/Sahara/Willys); 37x12.50 (Rubicon)
• Installation Type: Bolt-on, no cutting or drilling
• Warranty: Limited Lifetime (JKS components); FOX Shocks covered by FOX limited warranty
• Made in USA

Included Components

• 2x JSPEC Diesel-Specific Dual-Rate Front Coil Springs (JSPEC1252 - 2.5" Diesel/392)
• 2x JSPEC Diesel-Specific Dual-Rate Rear Coil Springs (JSPEC1259 - 2.5" Diesel/392)
• 2x FOX 2.0 Adventure Series IFP Front Shocks (custom-valved)
• 2x FOX 2.0 Adventure Series IFP Rear Shocks (custom-valved)
• 1x Pair Front Control Arm Correction Brackets (7GA steel, fully boxed - JKS6201)
• 1x JKS Front Adjustable Track Bar
• 1x Rear Track Bar Bracket
• 1x Pair JKS2033 Quicker Disconnect Front Sway Bar Links
• 1x Pair Rear Extended Sway Bar Links
• 1x Set Front and Rear Bump Stop Extensions
• 1x Installation hardware pack (JSPEC1310 J-Kontrol Main Box Kit)

Product Description

The JKS JSPEC166KFA is a complete 2.5" J-Kontrol suspension lift system for 2020-2026 Jeep Wrangler JL Unlimited 4-Door models equipped with the 3.0L EcoDiesel V6 or 6.4L Rubicon 392 V8. J-Kontrol builds on the J-Venture foundation by adding the defining upgrade: Front Control Arm Correction Brackets fabricated from heavy-duty fully boxed 7GA steel that lower the frame-side control arm mounting point, flattening operating angles at 2.5" of lift to closely mimic factory suspension geometry. This improves on-road handling and corrects caster without replacing the factory control arms.

The Diesel/392-specific calibration is built into the coil springs: JSPEC1252 front and JSPEC1259 rear springs are wound specifically for the heavier front-end weight and different suspension loads of the EcoDiesel and 392 V8 engines at 2.5" of lift - distinct from both gas-engine springs and the 3.5" Diesel springs used in higher-lift kits. Custom-valved FOX 2.0 Adventure Series IFP shocks, a JKS front adjustable track bar, JKS2033 Quicker Disconnect sway bar links, and rear extended sway bar links complete the system. For the J-Konnect upgrade with J-Link lower control arms for Diesel/392, see JSPEC163KFA. Does not fit 4xe models.