When to Use Bronco’s Front or Rear Locker

Picture this: It’s a cold winter day on Drummond Island off the eastern tip Michigan’s Upper Peninsula in December 2021. Average lows are around 14°F, with highs of about 27.1°F. A dense several inches of snow had fallen overnight on top of older snow, and I was about to head out with Dan, retired Ford off-road and 4-wheel-drive engineer, hot cup of coffee for each of us and map in tow.

We had arrived on the island the night before, after finishing some winter test driving in Bronco Nation’s ambassador unit, a 2021 Bronco Badlands with the Sasquatch Package, at a nearby proving ground. There, the Bronco excelled at everything it touched on the 800 acres of snow, ice, and bare pavement. That was one of my first opportunities to truly experience the Bronco in my home state, and it felt great.

Good memories in mind and just a casual tour of some easy trails planned, plus booted and suited up with warm winter gear, we made the call to leave Dan’s modified F-150 back at the lodge since the purpose of this trip was to experience the Bronco and me learn it. Both of us stand by the advice to not wheel alone if possible. We knew there was a possibility of having to turn our off-road jaunt into a hike back on that crisp sunny morning.

We were nearly prophetic.

What Is a Locker, and What Does It Do?

A locker, or locking differential, is an off-roading aid that forces both wheels on the same axle to rotate at the same rate. The differential is the “pumpkin” you see in the middle of an axle, and on the Bronco, the differentials are either open (unlocked) or can have the capability to be locked with the push of a button on the dash.

Like 4-wheel drive, lockers are a tool to get more traction so you can get your Bronco unstuck or keep it moving over terrain and obstacles. Ford made the Bronco available with an electronic front and rear locker.

Read: When to Use Bronco’s 4H, 4L, and 4A

Do I Have Lockers?

All Broncos have 4-wheel drive (4WD), but not every Bronco has a front locker, rear locker, or both, depending on the trim, year, and how it was optioned. Without getting bogged down (pun unintended), all Sasquatch Broncos have both, as does the Raptor and non-Sasquatch Badlands. The retired Black Diamond had a rear locker standard and in the early years, other non-Sasquatch trims could be optioned with a rear locker. No Bronco has just a front locker.

image: Ford

If you’re unsure, look at the Hero Switches, the buttons on your dashboard above the center screen, to check. If you have five or six buttons, then you have a front locker, with the second button from the left side of the button tray (A) activating it. If you have at least four buttons, you have a rear locker (B). Three buttons mean both your differentials are open and cannot be locked (unless you go aftermarket, which we can cover in a future article).

Why Use Them

If you have at least the rear locker, congratulations! Your Bronco is that much more ready for escapades. And if you don’t, don’t worry; you still have 4WD and can get through plenty of trails without needing them.

Back to what we said above, a locker forces both wheels on the same axle to turn at the same rate. With an open differential, whether you’re in 4WD or not, all power is sent to the wheel with the least amount of resistance. If you're in drive, pressing the gas, and not going anywhere, then that means it’s the one up in the air or spinning helplessly in the snow, sand, or on rock, making that entire axle now useless for forward momentum. However, if you are in 4WD, you do at least have one more axle and up to two wheels with traction, which is why so many vehicles can get by on trails fully unlocked.

Sometimes, like on big obstacles or sloppy ground, 4WD is not enough –– there’s still not enough traction to move forward or reverse. That’s where locker magic comes in. Engage one (or both, called twin locking), and the wheel that is spinning uselessly is now tied to the other wheel on that axle. Both wheels get to turn at the same speed, and the other wheel has a chance to grab.

In short, we use lockers to make up for a lack of traction and contact with the ground. In independent front suspension (IFS) vehicles like the Bronco, this is fantastic, since we have less articulation, or flex, than solid front axle vehicles and often have a wheel lifted slightly … or a lot.

Lockers Can Save the Day

Back on Drummond Island, Dan and I were having a great time, laying down fresh tracks in untouched snow. Drummond can become very wet (so wet, that Ford first showed off the Everglades to the press there), and under the snow was thick ice and sloshy mud and water, despite the cold temps. We went back in forth through these areas, breaking through but maintaining plenty of traction. Until one where we didn’t.

The heavy front of our 2.7L Badlands plowed through some ice into the muddy waters and immediately lost all forward progress. We were stuck, and reversing did nothing.

Had Dan and I been out in two vehicles or if the Bronco had a winch, we would have been fine in a Bronco without any lockers. A tug or pull, and we would likely be free. This is one reason why lockers aren’t necessary, but it’s advised to go out with another capable vehicle and gear.

We didn’t have another vehicle on the trail, but we did have lockers, both front and rear.

How to Engage and Disengage the Bronco’s Lockers

Ford made using the lockers in the Bronco incredibly easy. All it takes to engage or disengage (lock or unlock) the locking differential is a button push, and it can be done on the fly. You can click it on when you need it and turn it off when you don’t. Certain G.O.A.T. Modes will also engage them, but you can turn them off without leaving the mode. In addition, factory lockers automatically disengage when the vehicle speed exceeds a set value and reengages when the vehicle speed goes below a set value.

The front locker is only available in 4L. The maximum engagement speed is 20 mph, and it will automatically disengage at 25 mph. If you drop back to 20 mph or lower, it will automatically reengage.

image: Ford

The rear locker is more readily available, and potentially at higher speeds, depending on G.O.A.T. Mode and what the transfer case is in.

image: Ford

In our case, on Drummond, we were in 4L. Dan shifted the Bronco into reverse, engaged the rear locker, and steadily pushed the gas. For the first time that trip, the Bronco did not do what we wanted. Even in 4WD and with the rear axle locked, those back tires, turning at the same rate, did not have enough traction to pull the Bronco back. At this moment, visions of the miles-long hike flitted through my brain. Still, we had the front locker to try. One more button push, a little more finessing, and we were out of our pit.

When Should I Use the Bronco's Front Locker, Rear Locker, or Both?

Like deciding which 4WD range to use on what terrain, there are some hard rules and some areas where you have choice. Before we get into front, rear, or both, let’s cover proactive locker use or reactive locker use.

Dan and I reacted with the lockers; we used them once we were stuck. This is one way to off-road. However, doing so can cause more damage to the trail than proactive use, if you dug in before engaging them. With reactive use, you could also cause damage to your vehicle if you were coming in hot and get stuck or used momentum to clear an obstacle. Proactive use can be gentler on both the trail and your Bronco. You may not end up digging up the trail, and if you have front wheel lift but an engaged locker, you won’t suddenly slam a singular spinning wheel down on the ground, which can cause CV joint damage. To proactively use lockers, survey the land and obstacle, and before you’re stuck, engage a locker. Just remember that any locker use can come with risks. More on those below.

So, which method to use, proactive or reactive? Some people may notice that Ford gave more Broncos the option for rear lockers. Does that mean it’s the more useful one? Why did the motor company do that?

Rear lockers aren’t necessarily “better,” but using one does come with less risk of damage to other components, especially in an IFS vehicle with its CV joints and more. Plus, they can be easier to install, making them more cost-efficient for the manufacturer.

If you only have the rear locker, that will be the one you’ll be using. But even if you have both, it still may be the one you engage first. Talk to enough off-roaders, and you’ll find believers in “always front first,” “always rear,” and even “I have both; I’m locking both.”

Thankfully, if you know your vehicle and can read terrain, you can choose your own position, so long as you follow a couple rules that help you avoid risks.

• Don’t use lockers on dry pavement. Lockers are for off-road use, and perfect for uneven and loose traction surfaces like sand, snow, mud, and rocks. Lockers create driveline bind. Tire lift and low traction release the bind, making them OK to use on the right surface.
• Don’t engage either locker when cruise control or Trail Control is selected and active. The differential could have difficulty engaging.
• Don’t use your front locker going down hills. Do use your rear locker on steep, rutted hill descents, however. It can keep your vehicle from shooting away or tracking sideways if a rear tire lifts. Be sure to put it in low gear for the engine braking benefits!
• Don’t use your front locker going up hills that have a turn. Or use it, but disengage it before turning. Steering ability is decreased with the front locker on. Avoid using your front locker while you are in full steering lock (wheel turned completely one way). You’re at more risk of damaging your CV joint.
• Don’t leave them on. Anytime you’re not using either, turn them off. Some off-roaders will say that they engage their rear locker the minute they shift into 4WD. If you attend Bronco Off-Roadeo (and you should, if you can and haven’t!), the trail guides recommend using lockers as needed –– both proactively and reactively –– and then turning them off to avoid hitting flat, high-traction terrain with them on. You can wear your tires faster, or worse.
• Don’t use your lockers on a slide slope with loose surfaces. You want the vehicle to send power to your uphill wheels, and with the axles unlocked, it has a chance to. Otherwise, you may crabwalk your Bronco off the edge.

With the rules out of the way, think of the rest with this in mind: In drive, your front locker pulls your Bronco up an obstacle, and your rear locker pushes. Which fits the situation you’re in better? Where’s the weight of your vehicle, and where do you need to go?

Front lockers are great for getting your Bronco up a ledge and straight hills where you don’t need to turn. Rear lockers are great for water crossings, sand, and inclines and declines. Note that on hills with only the rear locker on, you may find your Bronco pivots slightly, with the front end going side to side more, but you’ll still have steering capabilities to counteract.

You can lock both, if you have them, when going up a hill and the rear locker is not enough. Another good time to try them is if you’re bogged down in sand but before you’re buried too deep. Always go slow and steady on the throttle!

Ready to Lock In?

We hope this information makes you feel more confident about using lockers out on the trail. What tips and reminders did we not include that you’d like to mention? Did it leave you with any questions? How often do you need a locker on the trail, or what do you do if you’re stuck and don’t have them? Talk about it below!