Complete On-Road, Overland & Off-Road Systems Guide: Jeep® 2018-2026 Wrangler JL & Gladiator JT

OFF-ROAD SYSTEMS GUIDE (2018–2026) — Configuration Matrix · Technical Reference · Tire Size Guide · Trim Comparison
Configuration Matrix
Terrain Scenarios & Settings
Technical Guide
Introduction 1. Transfer Case 2. Electronic Controls 3. Tru-Lok Lockers 4. Sway Bar Disconnect 5. Selec-Speed Control 6. Off Road+ Mode 7. Off Road Pages 8. Tires & Upgrade Paths
Trim Compatibility
Feature Matrix by Trim Transfer Cases Differential Lockers Sway Bar Disconnect Selec-Speed Control Off Road+ Mode
ABS
Anti-lock Braking System
BLD
Brake Lock Differential
TCS
Traction Control System
ESC
Electronic Stability Control
ERM
Electronic Roll Mitigation
4HF
4H Full-Time AWD (clutch-variable)
4H-PT
4H Part-Time (rigid 50/50 lock)
4L
4-Low Range (4.00:1 reduction)
Off Road+
Terrain calibration mode (4H = sand/speed, 4L = crawl)
SSC
Selec-Speed Control (off-road cruise)
Tru-Lok
Electromagnetic differential locker (front & rear)
Sway Bar
Electronic anti-sway bar disconnect
ABS — Anti-lock Braking System ALWAYS ACTIVE
Pulses brake pressure per wheel to prevent wheel lockup during hard braking, allowing you to steer during an emergency stop. Active in all transfer case positions, all electronic modes, and cannot be disabled by any button or control.
BLD — Brake Lock Differential ALWAYS ACTIVE
Applies braking to individual spinning wheels to simulate a limited-slip differential — redirecting torque to the wheel(s) that still have grip. This is your primary cross-axle traction aid when the Tru-Lok lockers are not engaged, since the differentials are otherwise open. BLD remains active even with ESC fully off, and even in 4L where all other electronic systems are auto-disabled.
AUTO badge (TCS / ESC / ERM)
When you see AUTO on a TCS, ESC, or ERM row, it means that system automatically disables itself when 4L (Four-Low) is engaged — no button press required. The vehicle's control module cuts those systems whenever low range is selected, and restores them automatically when you shift back out of 4L. This is unrelated to the 4HF (4WD Auto) transfer case mode — AUTO here refers solely to the electronic chassis systems self-managing in 4L.
RAISED badge (ESC / BLD)
Off Road+ mode raises the intervention threshold for ESC and BLD — the systems remain fully active but only step in when wheel-speed deviation or vehicle instability becomes more extreme than normal. In practical terms: on sand, standard BLD thresholds can brake a slightly-spinning tire prematurely, which digs the tire in and loses momentum. A raised threshold lets the tire spin a little more freely before applying braking, preserving the forward momentum that keeps you from getting stuck. Not "off," not "normal on" — deliberately calibrated to be less intrusive on loose surfaces.
The single most important principle in off-road driving is start with the minimum configuration the terrain requires and add complexity only when that proves insufficient. This is not timidity — it is precision. The reasons are practical:
① Locked differentials eliminate steering authority.
Using them where they are not needed means sacrificing control you would otherwise have.
② Most Moab obstacles are completed in 4L with BLD only — no lockers at all.
Good tire placement matters more than any electronic system.
③ Electronics compensate for traction deficits but cannot overcome physics.
Tire pressure, approach angle, and momentum are the three most important variables in any off-road scenario.
④ Adding systems mid-obstacle is dangerous.
Engage everything you plan to use before committing to an obstacle — never attempt to engage a locker or change transfer case position while actively climbing or navigating technical terrain.
SELECT A TERRAIN TYPE TO FILTER · ALL SCENARIOS SHOWN BY DEFAULT
Technical Guide
Eleven off-road controls. One layered system. Every terrain scenario mapped.
From a pavement-safe full-time AWD mode all the way to a fully locked, sway-bar-disconnected rock crawler with a ~86:1 crawl ratio, modern Jeep® Wranglers and Gladiators give you a remarkably deep stack of off-road controls. Understanding what each setting does mechanically and electronically — and critically, how they interact with each other — is the difference between using this capability confidently and getting stuck or damaging hardware. This guide covers every control, every combination, and maps them to specific terrain scenarios.

Reference vehicle: 2026 Wrangler Rubicon X. Throughout this guide we use the Rubicon X as our reference because it ships from the factory with all eleven controls active — making it the most complete illustration of the full system. Most of these controls are available across the broader Wrangler JL and Gladiator JT lineup depending on trim and packages installed. The Trim & Model Compatibility section maps exactly which features are available on every trim from Sport to 392. The three things that make the Rubicon X specifically unique are its full-time Rock-Trac HD transfer case (five positions instead of four, adding the pavement-safe 4HF AWD mode that the standard gas Rubicon lacks), 4.56:1 axle gears (vs. 4.10 on the standard Rubicon), and factory 35-inch tires — changes that push the crawl ratio to ~86:1 and give it a genuine daily-driving AWD mode.

The Eleven Controls at a Glance
The controls fall into four natural groups. You layer them in roughly this order as terrain demands more capability:
Group 1 — Torque Routing (Transfer Case)
Control What it does in one line
① 2H — Two-Wheel Drive Rear wheels only. Front axle physically disconnected. Highway default.
② 4HF — Full-Time AWD Rear-biased AWD via clutch pack; up to 50/50 on slip. Safe on dry pavement. Rubicon X / 392 / 4xe only.
③ 4H Part-Time Rigid mechanical 50/50 front/rear lock. Loose surfaces only — binds on dry pavement.
④ 4L — Four-Low 4.00:1 planetary reduction + rigid 50/50 lock. ~86:1 crawl ratio. Slow technical terrain.
Group 2 — Electronic Traction Stack
Control What it does in one line
⑤ TCS — Traction Control Cuts engine power and/or brakes spinning wheels. Disable for sand, mud, climbs requiring momentum.
⑥ ESC — Stability Control Selectively brakes individual wheels to correct understeer/oversteer. Raises threshold in Off Road+ 4H; fully disables in 4L and ESC Full Off.
⑦ BLD — Brake Lock Differential Brakes a spinning wheel to simulate a limited-slip differential. Always active — cannot be disabled. Your cross-axle traction aid when lockers are not engaged.
Group 3 — Mechanical Traction & Suspension
Control What it does in one line
⑧ Rear Tru-Lok Locker Dog-clutch mechanical spool — both rear wheels forced to identical speed. 4L standard; 4H Part-Time with Off Road+ + ESC Full Off. Rubicon family + 2024+ Willys + Gladiator Mojave.
⑨ Front Tru-Lok Locker Same as rear but on the front axle. 4L only; rear must lock first. Eliminates most steering authority — last resort. Rubicon family only.
⑩ Sway Bar Disconnect Electrically decouples the front anti-roll bar for maximum suspension articulation. Both 4H and 4L; auto-reconnects above 18 mph. Rubicon family only.
Group 4 — Driver Assistance
Control What it does in one line
⑪ Off Road+ Mode Two completely different programs in one button: in 4H it's a high-momentum sand/desert calibration; in 4L it's a precision rock-crawl calibration. Also enables rear locker in 4H Part-Time. Rubicon family, 2024+ Willys, Gladiator Mojave.
Selec-Speed Control (off-road cruise, 0.6–5 mph in 4L) and Off Road Pages (real-time telemetry) are covered in dedicated sections below. They are driver-assistance and information tools rather than traction controls, but are equally important for getting the most out of the system.

How to use this guide: The sections below go deep on each control group — the mechanics behind them, when to use them, and how they interact. If you want terrain-specific configurations first, the Configuration Matrix at the top maps every scenario to the exact settings. The most repeated advice from experienced Rubicon owners applies regardless of trim: start with the minimum settings the terrain requires and add complexity only when it proves insufficient.

1. The Transfer Case: Master Control for Torque Routing
The Rubicon X's Rock-Trac HD Full-Time transfer case is a five-position unit based on the NV241 platform. It uses a chain drive, a planetary gear set for low range, and — critically — an electronically controlled multi-plate clutch pack that enables the full-time mode. The standard Rubicon uses a four-position part-time-only variant without the clutch pack.
2H — Two-Wheel Drive High
Power goes to the rear wheels only. The front axle is physically disconnected via a Front Axle Disconnect (FAD) module. Torque split is 0/100 front/rear. This is your highway default — best fuel economy, no drivetrain drag from the front axle.
4HF — Four-High Full-Time (4WD Auto)
The front axle reconnects, and the electronically controlled clutch pack sits between the front and rear output paths. Under normal traction, the system is rear-biased (~48/52 front/rear). When wheel-speed sensors detect rear slip, the clutch pack progressively locks, sending up to 50/50 torque front/rear. Because the clutch can slip, the front and rear axles are allowed to rotate at different speeds in turns. This means 4HF is safe on dry pavement — no binding, no crow-hop. This is exclusive to the Rubicon X (and 392/4xe models); the standard Rubicon's part-time-only transfer case does not have this mode.

Important for sand driving: While 4HF is convenient, it's suboptimal for sustained sand use. The clutch pack can overheat during prolonged off-road driving, and there's a slight engagement delay as the system reacts to rear slip. For committed sand/dune driving, 4H Part-Time is preferred — it provides instant, continuous 50/50 power distribution with no clutch pack in the loop.

4H Part-Time — Four-High Part-Time
The front and rear driveshafts are mechanically locked together through the transfer case chain with no center differential and no clutch slip. Both axles are forced to rotate at identical speed. Torque split is a rigid 50/50. This provides maximum traction but causes drivetrain binding ("crow-hop") on high-traction surfaces. Never use on dry pavement. Use on loose, slippery surfaces only — gravel, snow, mud, sand.
4L — Four-Wheel Drive Low
Engages the 4.00:1 planetary reduction gear set while also fully locking the clutch pack (or chain on part-time models), producing a rigid 50/50 front/rear split identical to 4H Part-Time. The 4:1 reduction multiplies engine torque fourfold before it reaches the axles. Combined with the Rubicon X's 4.56:1 axle gears and the 8-speed automatic's 4.714 first gear, this yields a crawl ratio of approximately 85.9:1 — meaning the wheels turn 86 times slower than the engine. This is your slow-and-controlled mode for technical obstacles.
Shift-on-the-fly Rules
You can shift freely between 2H, 4HF, and 4H Part-Time at any speed while driving — no need to stop. Shifting into or out of 4L requires the vehicle to be nearly stopped (under 2–3 mph) with the automatic transmission shifted to Neutral first, because the planetary gear set must synchronize.
2. Electronic Control Stack: Three Distinct Levels
The Wrangler's electronic chassis control operates in three distinct levels, and understanding them is essential because one critical subsystem — Brake Lock Differential — stays active in all three.
System What it does When to reduce/disable
ABS
Always Active		 Prevents wheel lock-up under hard braking by pulsing brake pressure per wheel. Allows steering during emergency stops. Cannot be disabled. Works in all modes.
BLD
Always Active		 Brakes individual spinning wheels to simulate a limited-slip differential. Redirects torque to wheels with grip. This is your electronic LSD — it is always working even when all other systems are "off." Cannot be disabled. Even "ESC Full Off" still includes BLD.
TCS
Single-press ESC button		 Cuts engine power when wheels spin beyond a threshold. The primary system that feels like it "kills the throttle" when you want to maintain momentum (e.g. in sand or mud). Disable for sand, deep mud, loose climbs — anywhere momentum matters more than individual wheel speed control.
ESC
Hold ESC button 5 sec		 Uses selective braking to correct understeer and oversteer. Compares steering input to actual vehicle direction and intervenes. In Off Road+ mode, its threshold is raised (less intrusive) rather than fully disabled. Fully disable only in ESC Full Off mode. In sand & dunes with rear locker, full disable gives the cleanest feel. Keep raised/on for most other scenarios.
ERM
Disables with ESC off		 Detects imminent rollover by monitoring lateral acceleration and yaw rate. Applies braking to the appropriate wheels to reduce roll tendency. Particularly relevant during high-speed direction changes. Disables automatically when ESC is fully off. Keep on for any high-speed driving including desert tracks.
The Three States of Electronic Intervention
Full On: All systems active at factory thresholds. Correct for pavement, rain, and most on-road conditions.
Partial Off (single press ESC): TCS engine cut disabled. ESC threshold raised by Off Road+ if active. BLD and ABS unchanged. Good for moderate off-road — the vehicle won't kill throttle mid-obstacle but still catches major slides.
Full Off (hold ESC 5 sec): TCS and ESC disabled. ERM disabled. Only ABS and BLD remain. Required for rear locker engagement in 4H-PT. Best for sand and dunes where predictable, uninterrupted throttle response is critical.
Automatic Behavior in 4L
When you shift into 4WD Low, the system automatically enters Full Off below 40 mph — no button press needed. ESC and TCS are disabled. BLD remains active. The ESC OFF button has no additional effect in 4L.

Critical takeaway: BLD is always working. Even with every electronic system "off," the vehicle is still using brake pressure to simulate a limited-slip effect on each axle. This is important because the Rubicon's differentials are open when the lockers are not engaged — there is no mechanical limited-slip device. BLD is your only cross-axle traction aid until you engage the Tru-Lok lockers.

3. Tru-Lok Differential Lockers
Tru-Lok electronic locking differentials are electromagnetically actuated, positive-locking dog-clutch mechanisms — not friction clutches. When you press the locker switch, an electromagnetic coil energizes inside the differential carrier. This creates friction on a drag plate, forcing actuator pins up ball-ramp grooves, which push a sliding locking collar into engagement with square dog-ear teeth on the side gear. The result is a true mechanical spool — both axle shafts on that axle are forced to rotate at identical speed with zero slip. This delivers 100% of available torque equally to both wheels.
Engagement Rules by Transfer Case Position
T-Case Position Rear Locker Front Locker Required Conditions
2H Not Available Not Available —
4HF (Full-Time) Not Available Not Available Clutch pack incompatible with locker
4H Part-Time Rear Only Not Available Off Road+ active + ESC Full Off (5-sec hold)
4L Available Available Under 10 mph. Rear must lock before front.

Critical: 4HF cannot engage the rear differential locker under any circumstances. The clutch pack mechanism in 4HF is fundamentally incompatible with a locked rear differential. For sand driving with the rear locker, you must use 4H Part-Time, not 4HF. This is why the gold standard sand configuration is: 4H Part-Time + Off Road+ + ESC Full Off + Rear Locker.

Rear Locker in 4H Part-Time: The Exact Sequence
  1. Engage 4H Part-Time (slow below 55 mph, turn dial to 4H, confirm 4WD indicator)
  2. Press the Off Road+ button — the OR+ indicator illuminates
  3. Press and hold the ESC button for approximately 5 seconds until the cluster displays "ESC OFF" — a single press only gives partial disable, which is insufficient
  4. Press the rear locker button — indicator flashes during tooth engagement, then goes solid when locked

Order matters: Steps 2–4 must be performed in sequence. If the cluster displays "Shift to 4 Low," either Off Road+ is not active or ESC is not in Full Off state. The locker will also disengage automatically if Off Road+ is turned off, ESC exits Full Off mode, or the ignition is cycled.

Model Year & Trim Variations
2018–2020 JL Rubicons lack Off-Road+ entirely. Lockers are 4L only from the factory. Aftermarket devices (Tazer Mini, TrailDash3, JSCAN) are required for 4H locker use.
2021+ JL/JT Rubicons gained Off-Road+ and with it, rear locker capability in 4H Part-Time.
4xe Rubicons (2021–2023) did not receive Off-Road+ until the 2024 model year, so those earlier 4xe models are also 4L-only for lockers.
When to Use Which Locker
Rear only (most common): Both rear wheels forced to drive equally. Front axle remains open and fully steerable. Correct for sand, most rock crawling, mud, and hill climbs. This is the configuration for the majority of serious off-road situations.
Both locked (last resort): Four-wheel spool. Maximum traction but zero steering authority — the vehicle goes where momentum takes it. Use only for extreme straight-line obstacles where traction is completely inadequate with rear-only. Never engage the front locker while turning.
Auto-disengage: Both lockers disengage automatically above approximately 30 mph (4L) or when exiting Full Off state (4H-PT rear locker). Below 10 mph they re-lock if the switch is still active.
4. Electronic Anti-Sway Bar Disconnect
The front anti-roll bar (sway bar) normally limits how far the suspension can articulate to reduce body roll at speed. Off-road, this becomes a liability: with the sway bar connected, if one front wheel drops into a depression, the opposite wheel is pulled downward too — reducing contact patch and traction. Disconnecting the sway bar allows each front wheel to travel through its full suspension range independently.
On the Rubicon, an electric motor slides a splined collar that physically disconnects the sway bar end links. Press the button and the bar is decoupled in seconds. It automatically reconnects when vehicle speed exceeds 18 mph — a safety feature to restore stability if speed builds. The JL Wrangler improvement over the older JK is that this system works in both 4H and 4L, not just 4L.

When to use it: Any rock crawling or highly uneven terrain where you need both front tires to maintain ground contact simultaneously. Disconnect at the trailhead before articulation is needed — not in the middle of an obstacle. At 18 mph it reconnects automatically, so on faster dirt roads it simply stays connected.

5. Selec-Speed Control (SSC) — Off-Road Cruise
Selec-Speed Control is fundamentally different from Hill Descent Control found on most other vehicles. HDC uses brakes only and works on descents only. SSC uses both throttle and braking and works on ascents, descents, and flat terrain. It is an off-road cruise control that holds a set speed between approximately 0.6 and 5 mph, freeing the driver to focus entirely on steering.
How to Engage SSC
  1. Must be in 4L with automatic transmission (not available in 4H or with manual gearbox)
  2. Press the SSC button on the center console or steering wheel
  3. Set your target speed using the + / − buttons (typically 1–3 mph for rocks, 1–2 mph for descents)
  4. Lift both feet completely off the pedals — SSC manages throttle and braking automatically
Pressing the brake pedal pauses SSC (it resumes when released). Pressing the throttle overrides temporarily (SSC resumes). The system does not cancel on brake or throttle input — unlike conventional cruise control — because the driver may need brief manual input mid-obstacle without losing the set speed.

Why this matters: On a sustained rock descent, SSC prevents brake fade by using engine braking and measured brake application rather than a continuous hold. Riding the brakes on a long rocky descent generates heat that can cause brake fade at exactly the moment you need them most. SSC applies and releases automatically, managing temperatures across the descent.

Equipment Note
The 3.6L V6 on some JL model years receives Hill Descent Control (brakes-only descent management) rather than the full Selec-Speed Control (throttle + brakes, works in all directions). The 2.0L turbo consistently comes with SSC. Check your specific build sheet or window sticker to confirm which system you have.
6. Off Road+ Mode: One Button, Two Different Programs
Off Road+ is the most misunderstood system on the Rubicon. It is not simply a "more aggressive off-road mode." It runs two fundamentally opposite calibrations depending on the transfer case position when the button is pressed. The same button press does different things in 4H versus 4L — because the physics of sand and rock crawling require opposite approaches.
Off Road+ in 4H — Sand & Speed Mode
When activated in any 4H position, Off Road+ configures the vehicle for momentum-based off-roading on soft or loose surfaces:
  • Throttle: More aggressive mapping — greater response for the same pedal input
  • Transmission: Holds gears longer at higher RPM rather than upshifting for economy
  • TCS: Engine cut disabled (same as single-press ESC), preventing power interruption mid-acceleration
  • ESC: Threshold raised — less likely to intervene during dynamic high-speed moves
  • BLD: Raised threshold — less aggressive brake application on spinning wheels (useful in sand where BLD can dig in)
  • Rear Locker: Enables rear locker engagement in 4H Part-Time (combined with ESC Full Off)

Design intent: Sand driving requires maintaining momentum above ~25 mph. Any system that interrupts power at the wrong moment can cause the vehicle to bog and become stuck. Off Road+ 4H removes those interruptions while keeping enough safety margin (raised ESC, not fully disabled) for dynamic surfaces.

Off Road+ in 4L — Rock Crawl Mode
When activated in 4L, Off Road+ configures for the opposite requirement — precision at very low speed over hard technical terrain:
  • Throttle: Softened mapping — more pedal travel required for the same torque, preventing accidental wheel hop on rock
  • Torque delivery: Smoother, more linear power curve optimized for 1–3 mph crawling
  • BLD: More aggressive threshold — brakes spinning wheels more quickly to redirect torque to traction wheels on uneven rock
  • ESC: Auto-disabled (4L disables ESC automatically), but BLD behavior is specifically tuned for rock surfaces

Design intent: On rock, sudden throttle inputs cause wheel hop — the tire bounces off the rock surface and loses all traction. Off Road+ 4L's softened throttle map makes smooth, controlled power application easier, even with less experienced inputs.

7. Off Road Pages (Uconnect Telemetry)
The Uconnect infotainment system includes a dedicated set of Off Road Pages — real-time vehicle data screens designed specifically for trail use. These are accessed through the main Uconnect menu under the "Off-Road" or "4x4" section depending on software version.
Page / Display What it shows & why it matters
Pitch & Roll
Inclinometer		 Real-time forward/backward (pitch) and side-to-side (roll) angles in degrees. Critical for avoiding rollover on side-hill traverses and knowing your approach angle on steep climbs. Most Jeep® enthusiasts consider roll angles above 30° a warning zone.
Steering Angle Current front wheel steering angle. Useful on tight switchbacks and for understanding articulation limits.
Compass Magnetic heading updated in real-time. Useful for navigating on trails without cellular signal where GPS maps may be unavailable.
Altitude Current elevation above sea level. Useful context for understanding terrain and for trip logging.
Transfer Case Status Confirms current T-case position (2H / 4HF / 4H / 4L) visually on screen — useful confirmation before committing to an obstacle.
Locker Status Shows front and rear locker engagement state. The indicator goes from flashing (engaging) to solid (locked) here as well as on the dash cluster.
Throttle & Brake % Real-time throttle and brake application percentage. Useful for learning smooth input technique — watching this on a rock crawl reveals how much unnecessary throttle most drivers apply.
Tire Pressure (TPMS) Individual pressure for each tire. Invaluable for airing down — monitor all four simultaneously rather than using a separate gauge on each tire. Note: TPMS sensors are optimized for on-road pressures and may show warnings below ~25 PSI.

Off Road Pages vs. Off Road+: These are completely separate systems. Off Road Pages are informational — they display data without changing vehicle behavior. Off Road+ is operational — it changes how the drivetrain, throttle, and electronics behave. You can have Off Road Pages open while in any drive mode, and enabling Off Road+ does not change what the pages display.

8. Tires: Pressure, Sizing & Upgrade Paths
Air Pressure: The Most Underused Tool
Reducing tire pressure increases the contact patch — the amount of tire touching the ground. On sand, this is the single highest-impact adjustment you can make, more significant than any electronic or mechanical setting. Airing from 35 PSI to 15 PSI dramatically increases flotation and traction. The Rubicon’s TPMS page lets you monitor all four tires simultaneously as you air down, and many trail guides specify PSI targets for specific terrain types. A portable compressor to re-inflate before returning to pavement is essential equipment for any serious off-road use.

The three most important variables in any off-road scenario are tire pressure, approach angle, and momentum — in that order. Every electronic system on this vehicle is secondary to getting these three right.

Factory Tire Sizes (2024–2026)
Every 2024–2026 Wrangler and Gladiator rolls off the line with tires between 31.5 and 34.4 inches. The JL platform’s generous fender clearances make upsizing more accessible than any prior Jeep generation, but each step up demands progressively more supporting modifications: a 33-inch swap on a Sport is nearly bolt-on, while a 40-inch build requires axle replacements, hydraulic steering, and a five-figure budget.
Trim Tire Size Diameter Axle Ratio Notes
Sport / Sport S P245/75R17 ~31.5" 3.45 Steel wheels (Sport), alloy (Sport S)
Sahara P255/70R18 ~32.1" 3.45 Only trim on 18" wheels
Willys LT285/70R17 ~32.7" 3.45 High-clearance fenders
Willys w/ Xtreme 35 Pkg LT315/70R17C ~34.4" 4.56 1.5" factory lift, BFG KO2s
Rubicon LT285/70R17 ~32.7" 4.10 Dana 44 front/rear
Rubicon w/ Xtreme 35 Pkg LT315/70R17C ~34.4" 4.56 Beadlock-capable wheels
Rubicon X (2024–25) LT285/70R17 std ~32.7" 4.10 Xtreme 35 Pkg optional
Rubicon X (2026) LT315/70R17C ~34.4" 4.56 Xtreme 35 now standard
Rubicon 392 LT315/70R17C ~34.4" 4.56 35s standard from 2024
The Xtreme 35 Tire Package bundles BFGoodrich KO2 all-terrains in LT315/70R17C, beadlock-capable 17×8" wheels with a +12mm offset, a 1.5-inch suspension lift, 4.56:1 axle gears, and a swing-gate reinforcement. Available as a ~$4,500 option on Willys and standard Rubicon; standard on the 2026 Rubicon X and all 392 variants.
Gladiator JT differences: The Gladiator Willys runs a smaller LT255/75R17 (~32.0") versus the Wrangler Willys’ 285/70R17 (~32.7"). The Mojave uses a unique +37mm wheel offset versus the standard +44mm. The Gladiator has no V8 option and its under-bed spare accommodates a maximum ~36.5-inch tire.
33-Inch Upgrades: The Easiest Path
Going from the Sport’s 31.5-inch stock tires to 33s is a modest 1.5-inch increase that requires no lift for street driving. The most popular size is 285/70R17 (32.7" actual, the stock Rubicon tire), which bolts directly onto the factory 17×7.5" wheels without spacers. At full steering lock, minor rubbing on the passenger side is possible — a common fix is adding a washer to the driver-side steering stop bolt to equalize lock angles.
One caveat: Sport models with 3.45 axle gears will feel noticeably sluggish with 33s. Models ordered with the 3.73 or 4.10 option handle 33s without any regearing concern.
35-Inch Upgrades: Real Work Begins
Non-Rubicon trims need 2.5 inches of lift minimum for 35-inch tires — most installers recommend 2.5–3.5 inches for off-road use. A quality spacer lift (ReadyLIFT SST, ~$400–600) is sufficient for street driving and light trails. Moderate-to-serious off-roading calls for a full suspension lift — MetalCloak, Teraflex Sport ST3, or Clayton Premium kits run $1,200–$4,000.
The 2024+ Willys has a significant advantage: it comes with Rubicon high-clearance fenders from the factory, making it the best non-Rubicon starting point for a 35-inch build. A Willys with a 2-inch lift clears 35s comfortably. Stock Sport/Sahara low-clearance fenders provide roughly 2 inches less room than Rubicon highline fenders — options include swapping to used Rubicon flares ($300–800), flat fenders ($400–$1,000), or trimming inner liners.
Rubicons are nearly bolt-on for 35s. Owner after owner confirms running 315/70R17 BFG KO2s on stock Rubicon wheels with no spacers, no lift, and zero rubbing. For dedicated off-road use with the sway bars disconnected, a 2-inch lift is recommended. The Rubicon’s 4.10 axle gears handle 35s adequately — the effective ratio drops to about 3.83, roughly equivalent to a Sahara running stock tires on 3.73 gears.
Regearing is strongly recommended for 35s on a 3.45-equipped Sport or Sahara. Jeep’s own Xtreme Recon package uses 4.56 gears with 35-inch tires — that’s the target ratio. Full regear cost (both axles): $1,500–$2,700 installed.
37-Inch Builds: The Serious Off-Road Sweet Spot
Running 37-inch tires requires a minimum 2-inch lift on a Rubicon, with 2.5 inches being the consensus sweet spot. The Rubicon X with the Xtreme 35 package (1.5-inch factory lift, +12mm offset wheels, 4.56 gears) gives you a head start.
Beyond the lift: bump stop extensions of at least 2 inches on both axles prevent tire-to-fender contact at full compression. The rear inner fender liner commonly needs trimming. Stock Rubicon wheels have too much backspacing (6.25") for 37s — you need aftermarket wheels with 4.5–4.75 inches of backspacing or 1.25-inch spacers. An upgraded tie rod and drag link (Synergy, RPM Steering) is highly recommended, as is a reinforced tailgate carrier hinge (Teraflex Alpha) for the ~85-pound 37-inch spare.
Regearing to 4.88 is the standard recommendation for 37s. On stock 4.10 gears, the transmission rarely reaches 8th gear and highway driving feels sluggish. DrivingLine’s instrumented testing confirmed that swapping to 4.88s with 37s “put our economy back to where we were on 35s.”
40-Inch Builds: A Full Platform Rebuild
Forty-inch tires transform a Wrangler into a fundamentally different vehicle. Minimum lift is 3.5–4.5 inches with long-arm suspension. The critical requirement is axle replacement: Dana 60 axles are the correct foundation. A Spicer Ultimate Dana 60 set runs $16,000–$20,000; Dynatrac ProRock 60s and Currie RockJocks fall in a similar range. Budget junkyard Dana 60 builds start around $8,000–$10,000.
Additional mandatory upgrades: hydraulic-assist steering (PSC Motorsports, ~$2,500–$3,500) because electric power steering cannot reliably turn 40-inch tires, 1350-series CV driveshafts, big brake kits (Teraflex Delta 14" or Dynatrac ProGrip), regearing to 5.13 or 5.38, and flat/highline fenders (Motobilt, GenRight). Total build cost: $25,000–$50,000+ for a serious off-road platform.
Gearing, Fuel Economy & Speedometer
The effective gear ratio formula: multiply the stock ratio by (stock tire diameter ÷ new tire diameter). A Sport with 3.45 gears dropping from 31.5" to 35" tires effectively becomes a 3.10 ratio — a 10% loss. The 8-speed ZF automatic is remarkably forgiving — its two overdrive gears partially compensate — but when you lose access to 8th gear entirely, highway fuel economy and cruising RPM suffer noticeably.
Real-world fuel economy losses follow a rough rule: ~2 MPG per size increment. A stock Rubicon averaging 20–23 highway MPG drops to 17–19 with 35s and 15–17 with 37s (both on stock 4.10 gears). Regearing recovers 1–2 MPG by allowing the transmission to operate in its optimal range.
Larger tires cause the speedometer to read slower than actual speed. A Sport going from 31.5" to 35" accumulates an 11.1% error — at an indicated 60 MPH, you’re actually traveling 66.7. Recalibration is essential: the JScan app with an OBD2 adapter (~$75 total) is the most popular budget option; the Tazer JL Mini ($150–280) offers plug-and-play convenience. These tools are also critical for ABS and stability control accuracy.
Axle Durability & Braking
The Dana 30 front axle (Sport, Sahara, Willys) handles 33s without concern and tolerates 35s for daily driving and moderate off-roading. At 37 inches, it becomes a genuine liability. Swapping to used Rubicon Dana 44 takeoff axles (~$2,000/pair) is more cost-effective than building up a Dana 30.
The Rubicon’s Dana 44s handle 35s effortlessly and manage 37s well for street and trail use. For aggressive rock crawling on 37s, an axle truss, upgraded ball joints, and heavy-duty differential covers add meaningful insurance. At 40 inches, even reinforced Dana 44s are operating at their limit.
Bigger tires degrade braking through increased rotational inertia and a longer lever arm requiring more brake torque. At 33 inches, stock brakes are adequate across all trims. At 35 inches on a Rubicon, stock brakes perform acceptably (upgraded pads like PowerStop Z36 help). At 37 inches and above, a big brake kit — Teraflex Delta, Dynatrac ProGrip, or Mopar HD — is strongly recommended.
Quick Reference: Lift & Gear Recommendations
Tire Size On Sport/Sahara On Willys On Rubicon On Rubicon X Regear Target (Auto)
33" 0–1.5" spacer lift Stock (bolt-on) Stock fitment Stock fitment Not needed (3.73+)
35" 2.5–3.5" + HC fenders 2–2.5" lift 0" street / 2" off-road Factory-equipped 4.56
37" 2.5–3.5" + HC fenders + axle concerns 2.5–3.5" + fender work 2–3.5" lift 1–2.5" additional lift 4.88
40" Not practical Not practical 3.5–4.5" + Dana 60s 3.5–4.5" + Dana 60s 5.13–5.38

The single most impactful decision isn’t the tire size itself — it’s whether to regear. The 8-speed automatic masks undergearing surprisingly well, but optimized gearing transforms the driving experience, recovers fuel economy, and reduces drivetrain stress. If you’re going to 35s on anything below 4.10 gears, budget $1,500–$2,700 for a regear from the start. And if 37s are the goal, plan the build holistically: lift, wheels, gears, steering reinforcement, bump stops, and brake upgrades form an integrated system where skipping one component compromises the others.

Trim & Model Compatibility
Off-road feature availability across Wrangler JL (2018–2026) and Gladiator JT (2020–2026) trim levels

Key changes for 2024+: Selec-Trac and Rock-Trac Full-Time removed as standalone options on gas Wranglers. Willys gained rear Tru-Lok electronic locker and Off-Road+ mode. All trims now include Off-Road Pages on the standard 12.3" Uconnect 5 infotainment system. The Rubicon X debuted as the only gas Wrangler with full-time AWD, factory 35s standard for 2026.

1. Transfer Case Modes by Trim
Three transfer cases serve the JL/JT platform: Command-Trac (2.72:1 low range, part-time only), Selec-Trac (2.72:1 low range, adds 4WD Auto full-time mode), and Rock-Trac (4.0:1 low range, available in both part-time and full-time variants). The 2024 model year eliminated Selec-Trac and Rock-Trac Full-Time as standalone options on gas Wranglers — making the 4xe or Rubicon X the only paths to factory full-time 4WD.
Trim Wrangler JL (Gas) Wrangler 4xe Gladiator JT
Sport / Sport S Command-Trac std; Selec-Trac optional 2018–2023, removed 2024+ Selec-Trac std (2024+) Command-Trac std; Selec-Trac optional on Sport
Willys / Willys Sport Command-Trac std; Selec-Trac optional 2021–2023, removed 2024+ Selec-Trac std (2023+) Command-Trac std
Sahara Command-Trac std; Selec-Trac optional 2018–2023, removed 2024+ Selec-Trac std (2021+) Command-Trac std
High Altitude Command-Trac std; Selec-Trac optional 2021–2023 Selec-Trac std Command-Trac std
Mojave — — Command-Trac std; Selec-Trac optional (2021+)
Rubicon Rock-Trac part-time std; full-time optional 2021–2023, removed 2024+ Rock-Trac full-time std Rock-Trac part-time std; full-time optional 2021–2023
Rubicon X (2024+) Rock-Trac full-time std Rock-Trac full-time std Rock-Trac full-time std
392 / Moab 392 Selec-Trac std (2.72:1, no 2WD mode) — —
2. Tru-Lok Electronic Differential Lockers
Front-and-rear Tru-Lok electromagnetic locking differentials have been a Rubicon hallmark since the JL's 2018 launch, but rear-only electronic lockers have spread to two other trims: Willys (from 2024) and Gladiator Mojave (from its 2020 debut).
Trim Front Tru-Lok Rear Tru-Lok Notes
Sport / Sport S ❌ ❌ Open diffs; BLD provides electronic traction simulation
Willys (2018–2023) ❌ ❌ Trac-Lok limited-slip differential (rear only), not electronic locker
Willys (2024–2026) ❌ ✅ Standard Upgraded from LSD to electronic Tru-Lok rear locker for 2024
Sahara ❌ ❌ Open diffs; optional LSD (2018–2023), removed 2024+
High Altitude ❌ ❌ Open diffs
Gladiator Mojave ❌ ✅ Standard Rear-only Tru-Lok since 2020 launch
Rubicon (all variants) ✅ Standard ✅ Standard Full front + rear Tru-Lok on all Rubicon, Rubicon X, Rubicon 4xe
392 / Moab 392 ✅ Standard ✅ Standard Inherits full Rubicon locker package
3. Electronic Sway Bar Disconnect
The push-button electronic front sway bar disconnect is standard and exclusive to every Rubicon-family trim: Rubicon, Rubicon X, Rubicon 4xe, Rubicon 392, and Moab 392, on both the Wrangler JL and Gladiator JT. It operates in both 4H and 4L (JL improvement over JK) below approximately 18 mph and auto-reconnects above ~25 mph. No other trim offers a factory sway bar disconnect of any kind.
4. Selec-Speed Control Availability
Selec-Speed Control is engine-dependent, not trim-dependent. SSC is a true low-speed off-road cruise control that manages both throttle and brakes to hold a set speed (0.6–5 mph) going uphill, downhill, or on flat terrain in 4-Lo. Hill Descent Control (HDC) is brakes-only, downhill-only. Neither system is available with a manual transmission.
Model Years 3.6L V6 (eTorque on auto) 2.0L Turbo I-4 3.0L EcoDiesel 6.4L V8 (392) 4xe PHEV
2018–2020 HDC only HDC only HDC only — —
2021 HDC only SSC SSC SSC SSC
2022–2023 SSC (nearly universal) SSC SSC SSC SSC
2024–2026 SSC standard SSC standard — SSC standard SSC standard
Gladiator JT: SSC has been standard on all trims and all engines with automatic transmission since the 2020 launch.
5. Off-Road+ Mode Availability
Off-Road+ adjusts traction control intervention, throttle mapping, transmission shift strategy, and Selec-Speed behavior for off-road driving. In 4-High it optimizes for higher-speed terrain (sand, gravel); in 4-Low it tunes for slow-speed crawling. The feature debuted on the 2020 Gladiator Mojave and expanded to the Wrangler Rubicon for 2021. The 2024 refresh brought it to the Willys trim.
Trim 2018–2020 2021–2023 2024–2026
Sport / Sport S ❌ ❌ ❌
Sahara / High Altitude ❌ ❌ ❌
Willys (JL, ICE + 4xe) ❌ ❌ ✅ Standard
Rubicon (all variants) ❌ ✅ Standard ✅ Standard
392 / Moab 392 — ✅ Standard ✅ Standard
Gladiator Mojave ✅ Standard ✅ Standard ✅ Standard
Gladiator Rubicon ❌ ✅ Standard ✅ Standard
6. Comprehensive Feature Matrix (2024–2026)
This table reflects the current-generation configuration after the 2024 refresh, covering both the Wrangler JL and Gladiator JT:
Feature Sport / Sport S Willys Sahara High Alt Mojave (JT) Rubicon Rubicon X 392 / Moab
Transfer case Command-Trac Command-Trac Command-Trac Command-Trac1 Command-Trac2 Rock-Trac PT Rock-Trac FT Selec-Trac
4WD Auto mode ❌ ❌ ❌1 ✅ (4xe only)1 Optional2 ❌ ✅ ✅
Low range ratio 2.72:1 2.72:1 2.72:1 2.72:1 2.72:1 4.0:1 4.0:1 2.72:1
Front Tru-Lok ❌ ❌ ❌ ❌ ❌ ✅ ✅ ✅
Rear Tru-Lok ❌ ✅ ❌ ❌ ✅ ✅ ✅ ✅
E-sway bar disconnect ❌ ❌ ❌ ❌ ❌ ✅ ✅ ✅
SSC (auto trans) ✅3 ✅3 ✅3 ✅3 ✅ ✅3 ✅3 ✅
Off-Road+ mode ❌ ✅ ❌ ❌ ✅ ✅ ✅ ✅
Off-Road Pages ✅ ✅ ✅ ✅ ✅ ✅ ✅ ✅
1 Gas High Altitude / Sahara: Command-Trac standard. 4xe versions get Selec-Trac standard. The gas Selec-Trac option was eliminated for 2024+.
2 Gladiator Mojave: Selec-Trac available as an option.
3 SSC availability on JL Wranglers is engine-dependent: confirmed standard with 2.0L turbo, 4xe, and 392. The 3.6L V6 received only HDC in 2021, gained SSC by 2022–2023, but some 2025 V6 builds may lack both SSC and HDC entirely. All Gladiator JT trims get SSC regardless of engine.
Data compiled from owner’s manuals, factory build sheets, dealer window sticker verification, and community documentation across 2018–2026 model years.
Configurations are guidelines based on terrain physics and community experience. Conditions vary — always start with minimum settings and add complexity only when terrain demands it. This content is provided for educational and informational purposes only. Information may be inaccurate, incomplete, or outdated — always verify configurations with your vehicle’s owner’s manual and consult qualified professionals before making off-road driving decisions. NepaConsultancy, LLC assumes no responsibility for errors, omissions, or outcomes resulting from use of this information.

© 2026 NepaConsultancy, LLC  ·  Privacy Policy  ·  Not affiliated with or endorsed by Jeep®, Stellantis, or FCA US LLC. Jeep® is a registered trademark of FCA US LLC.