Command-Trac, Rock-Trac or Selec-Trac? Jeep 4x4 Systems Explained
Last updated on October 26th, 2026 at 06:23 pm
Command-Trac is the Wrangler's basic part-time 4x4 with a 2.72:1 low range, standard on the Sport, Sport S and Sahara. Rock-Trac is the Rubicon's system, with a much deeper 4.0:1 low range in part-time or full-time form. Selec-Trac is a full-time case with a 2.72:1 low range and a 4H AUTO mode you can leave on for dry pavement. For 2026, Jeep fits it only to the Moab 392.
The table below comes straight from Jeep's 2026 Wrangler spec sheet and feature-availability guide. After it you'll find how to tell which one you have, which mode to use where, and what the Rubicon's 4:1 actually changes on the trail.
| System | Transfer case | Type | Modes | Low range | 2026 Wrangler trims |
|---|---|---|---|---|---|
| Command-Trac | NV241 | Part-time | 2H, 4H, N, 4L | 2.72:1 | Standard on Sport, Sport S (incl. Willys) and Sahara |
| Rock-Trac (part-time) | NV241OR | Part-time | 2H, 4H, N, 4L | 4.0:1 | Standard on Rubicon |
| Rock-Trac (full-time) | MP3022OR | Full-time | 2H, 4H AUTO, 4H PART TIME, N, 4L | 4.0:1 | Package option on Rubicon; included with Rubicon X |
| Selec-Trac | MP3022 | Full-time | 4H AUTO, 4H PART TIME, N, 4L (no 2H on the 392) | 2.72:1 | Standard on Moab 392 only |
How to tell which 4x4 system your Wrangler has
You don't need a VIN decoder. Look at the shifter and the dash.
- Count the shifter positions. Jeep's owner's manual describes two cases. A four-position case reads 2H, 4H, N, 4L. A five-position case adds 4H AUTO and calls the locked mode 4H PART TIME.
- Four positions? You have Command-Trac or part-time Rock-Trac.
- Five positions? You have Selec-Trac or full-time Rock-Trac.
- Look for a SWAY BAR button. In 2026 it comes only on the Rubicon (Rock-Trac, 4:1 low range) and the Moab 392 (Selec-Trac, 2.72:1). Both also get front and rear lockers. A Willys has a rear-only locker switch but still uses Command-Trac.
The window sticker or build sheet settles it if the Jeep has been modified. A swapped shifter or aftermarket switch panel can fool the visual check.
Which mode to use, by surface
The biggest practical difference between the systems is pavement. Every limit below comes from the Starting and Operating chapter of the 2026 Wrangler owner's manual.
2H: dry roads, every system
Jeep says 2H is for "normal street and highway driving on dry, hard surfaced roads." That's where Command-Trac and part-time Rock-Trac owners should live day to day. The Moab 392's Selec-Trac case has no 2H at all.
4H AUTO: the reason to want a full-time case
Only the five-position cases (Selec-Trac and full-time Rock-Trac) have it. Jeep says this case can be driven in 2H or 4H AUTO "for normal street and highway conditions on dry hard surfaced roads."
In 4H AUTO the front axle is engaged, but power goes to the rear wheels until the system senses slip. Then it brings in four-wheel drive on its own. Jeep notes that you pay for it with lower fuel economy than in 2H.
4H or 4H PART TIME: loose or slippery the whole way
This mode locks the front and rear driveshafts together, so both axles turn at the same speed. Jeep says it's for "loose, slippery road surfaces only." On hard-surfaced roads it "will cause increased tire wear and damage to the driveline components."
You can shift between 2H, 4H AUTO and 4H PART TIME stopped or moving. Jeep's preferred speed range is 0 to 45 mph. Our guide on using 4H on the highway covers the wet-highway gray area in more depth.
4L: steep, rocky or slow
Shift into or out of 4L while rolling at 1 to 3 mph. Use Neutral on an automatic or hold the clutch in on a manual, and don't pause the lever in N. Jeep caps 4L at 25 mph.
Jeep also notes that in 4L the engine turns about three times faster than in 4H at the same road speed. On Rubicon models it's about four times faster. If the shift fights you, our step-by-step on shifting into 4-Low when it won't go walks through the fixes.
What Rock-Trac's 4:1 low range actually buys you
Low range only matters once it's multiplied by first gear and the axle ratio. That product is the crawl ratio: how many times the engine turns for each turn of the tires. A higher number means a slower crawl at idle and finer throttle control on ledges and descents.
Jeep's 2018 Wrangler launch release lists 44.20:1 for an automatic Sport or Sahara and 77.2:1 for an automatic Rubicon. For 2026, Jeep quotes "up to 100:1" for the best-equipped Wrangler. We ran the same math for every factory combination Jeep lists for 2026 so you can see where your Jeep lands.
The speed columns use one 33-inch tire for every row so the builds compare fairly. Real tire sizes vary by trim, so plug yours into the calculator below.
| 2026 build | Transfer case | Transmission (1st gear) | Axle ratio | Crawl ratio | Speed at 1,000 rpm, 33-in. tire | Speed at 2,000 rpm, 33-in. tire |
|---|---|---|---|---|---|---|
| Sport, Sport S, Sahara | Command-Trac 2.72 | 8-speed auto (4.71) | 3.45 | 44.2:1 | 2.2 mph | 4.4 mph |
| Sport, Sport S, Sahara | Command-Trac 2.72 | 6-speed manual (5.13) | 3.45 | 48.1:1 | 2.0 mph | 4.1 mph |
| Willys (Sport S package) | Command-Trac 2.72 | 8-speed auto (4.71) | 4.10 | 52.5:1 | 1.9 mph | 3.7 mph |
| Moab 392, or Sport S with Xtreme 35 | Selec-Trac / Command-Trac 2.72 | 8-speed auto (4.71) | 4.56 | 58.4:1 | 1.7 mph | 3.4 mph |
| Rubicon | Rock-Trac 4.0 | 8-speed auto (4.71) | 4.10 | 77.2:1 | 1.3 mph | 2.5 mph |
| Rubicon | Rock-Trac 4.0 | 6-speed manual (5.13) | 4.10 | 84.1:1 | 1.2 mph | 2.3 mph |
| Rubicon or Rubicon X with Xtreme 35 | Rock-Trac 4.0 | 8-speed auto (4.71) | 4.56 | 85.9:1 | 1.1 mph | 2.3 mph |
| Rubicon with optional 4.88 axle | Rock-Trac 4.0 | 6-speed manual (5.13) | 4.88 | 100.1:1 | 1.0 mph | 2.0 mph |
Here's the payoff in plain terms. At the same engine speed, an automatic Rubicon crawls about 43% slower than an automatic Sport on 3.45 gears (77.2 vs 44.2). That's the difference between easing off a ledge on idle and riding the brakes down it.
The 4.56 axles that come with the Xtreme 35 package close some of the gap on a 2.72 case, but they don't get there. A Moab 392 still sits near 58:1.
Crawl Ratio and 4L Speed Calculator
Pick a factory build or type your own ratios after a regear. The calculator gives your crawl ratio and how fast the Jeep moves in first gear, 4L, at the engine speed you enter.
Quick fill (2026 Wrangler):
How it works: crawl ratio = first gear × low range × axle ratio. Speed in mph = rpm × tire diameter ÷ (crawl ratio × 336.13), where 336.13 converts inches per minute into miles per hour. Results are estimates, because loaded tires roll a little smaller than their nominal size.
Running bigger tires lowers your effective crawl ratio. Find your real diameter with our tire size calculator. To see which axle ratio would bring the gearing back, use the regear calculator for bigger tires.
Selec-Trac vs Command-Trac: is full-time worth it?
Off-road, they behave the same. Both have a 2.72:1 low range, and both lock front and rear together in 4H PART TIME or 4H and in 4L. The difference is on the road, where 4H AUTO lets you stop thinking about the lever during on-and-off snow, rain or gravel.
If you commute through a snow-belt winter, that's a real convenience. If your Jeep sees dry highways all week and trails on the weekend, Command-Trac does the trail work just as well.
Availability has moved around, which matters if you're shopping used:
- 2021: Jeep's 2021 Wrangler fact sheet lists Selec-Trac as available on Sport and Sahara models, and full-time Rock-Trac as optional on Rubicon.
- 2024: Jeep's 2024 Wrangler launch release lists Selec-Trac on the High Altitude, the Willys 4xe and the Rubicon 392, plus full-time Rock-Trac on the new Rubicon X.
- 2026: The 2026 feature-availability guide marks Selec-Trac "NA" on the Sahara and standard only on the Moab 392.
A used Sahara or Sport from earlier years may have either case. Check the shifter positions instead of trusting the trim name.
The Rubicon hardware that comes with Rock-Trac
The 4:1 case is only part of the Rubicon package. The 2026 feature guide pairs Rock-Trac with Tru-Lok electronic front and rear lockers and an electronic front sway-bar disconnect.
The Moab 392 gets the lockers and sway-bar disconnect too, but with the 2.72:1 Selec-Trac case. Since 2024, Rubicon models have also used a Dana 44 HD full-float rear axle. Each piece has limits from the owner's manual:
- Front and rear lockers: only in 4L at 10 mph or less, with both wheels on the axle turning at the same speed. They disengage above 30 mph and re-lock once you're back under 10 mph. More on when a diff lock helps.
- Rear-only lock in 4H: a high-speed off-road mode. It needs Off Road+ active and ESC in Full Off, and Jeep says it should not be used on any public roadway.
- Sway-bar disconnect: works in 4H or 4L. Jeep warns that you must reconnect the bar before driving on hard-surfaced roads or above 18 mph. The system tries to reconnect on its own over 18 mph. Our explainer on Jeep articulation shows why the extra wheel travel matters.
Older Wranglers: TJ and JK
TJ and JK Wranglers came with one of two cases. Jeep's 2005 4x4 systems report lists Command-Trac (2.72:1 low) as standard on the Wrangler and Rock-Trac (4:1 low) as standard on the Wrangler Rubicon. Both are part-time cases with the same 2H, 4H, N and 4L positions.
The JK kept the same pairing. Jeep's 2017 Wrangler owner's manual covers four-wheel drive operation for "Command-Trac I or Rock-Trac" only, and gives the same three-times (four-times on Rubicon) engine-speed rule for 4L. Neither Jeep source lists a full-time case for those Wranglers, so on a TJ or JK, 4H belongs on loose or slippery surfaces only.
Where most explanations go wrong
- "Rock-Trac is part-time only." Not on a JL. Jeep builds a full-time version (MP3022OR) with 4H AUTO and the same 4.0:1 low range.
- "The Sahara gets Selec-Trac." It could on some earlier JL model years. For 2026, Jeep's own guide says it can't.
- "Selec-Trac splits power 48/52 all the time." That describes the older center-differential Selec-Trac in Jeep's 2005 Selec-Trac description, the system used in Jeeps such as the Cherokee XJ. The JL owner's manual says 4H AUTO sends power to the rear wheels and brings in four-wheel drive when it senses slip.
- "4:1 low range means a 4x better crawl ratio." Compared with a 2.72 case, it's 1.47 times deeper on the same axle and transmission (4.0 ÷ 2.72). The larger gap you see between trims also comes from the Rubicon's 4.10 axles.
If you're still sorting out 4H, 4A and AWD across different brands, our breakdown of 4WD vs AWD vs 4A explains how those settings differ across Jeep, Ford and Toyota.
FAQ
Can I drive a Command-Trac Wrangler in 4H on the highway?
Only when the road is loose or slippery. Jeep says 4H on a four-position case is for "loose, slippery road surfaces only," and that driving in 4H on hard-surfaced roads causes extra tire wear and driveline damage.
Is Selec-Trac the same as AWD?
Its 4H AUTO mode works a bit like an automatic AWD system: rear-wheel drive until slip, then four-wheel drive on its own. Unlike a typical AWD crossover, it still has a 2.72:1 low range and a locked 4H PART TIME mode for the trail.
How fast can I go in 4L?
Jeep's limit is 25 mph for every JL Wrangler transfer case. Shift into and out of 4L at 1 to 3 mph.
All three systems take Mopar ATF+4 in Jeep's manuals. Our guide on when to change Wrangler transfer case fluid lays out the schedule by model year.
Does the Moab 392 have a 4:1 low range?
No. The 2026 Moab 392 uses the Selec-Trac full-time case with a 2.72:1 low range and 4.56 axles, which works out to about 58.4:1 with the 8-speed automatic.
I'm Suryashankar Dasgupta, the founder of Off-Road Handbook. I've been off-roading for years in the USA, including California and Texas, and have ridden mountain and desert terrain abroad. I've also driven a Jeep Compass for more than seven years, so I know the day-to-day side of Jeep ownership first-hand, from the Uconnect screen to the warning lights. Every guide here is researched from manufacturer owner's manuals, NHTSA recall and service-bulletin records and other trusted sources, checked against them before it is published, and corrected when we find a mistake. You can read how we work in our editorial policy: https://offroadhandbook.com/editorial-policy/
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