When and how to use axle lockers off-road

An axle locker ties both wheels on an axle together so they turn at the same speed, which is what gets you traction when one tire is in the air or spinning. Line up with the obstacle first, engage the rear locker, add the front only if you need it, then turn both off once you are through.

Lots of Jeeps, Broncos, and other trail rigs now leave the factory with electronic lockers. How they work internally is a topic for another month. Today is about using them well, because a locker used at the wrong moment does more harm than good.

The one rule that matters most

Never engage a locker while you are hard on the throttle or the drivetrain is loaded up.

The locking mechanism has to line up before it can grab. Under load it cannot, and forcing it is how you break parts. If you are already moving, keep it slow and as straight as you can, lift off the throttle, then hit the switch. Give it a second to catch. Most factory systems flash a dash light while the locker is trying to engage and hold it solid once it is locked, so wait for the solid light before you get back on the throttle.

Why a locker helps in the first place

A normal open differential lets the left and right wheels turn at different speeds, which is exactly what you want on pavement. The tradeoff is that an open diff sends power to the wheel with the least grip. Lift one tire off a rock and that tire spins freely while the one still on the ground does nothing.

A locker removes that choice. Both tires turn together and both keep pulling, so the one with traction can still move the vehicle.

The order of operations

1. Get lined up with the obstacle before you need the lockers.
2. Engage the rear locker.
3. Add the front locker only if you need more traction.
4. Cross the obstacle slowly and deliberately.
5. Disengage both once you are through.

Why the rear locker goes first

Every locker you engage costs you steering.

A rear locker makes the vehicle push a little wide and feel less willing to turn. A front locker is the bigger change, because both front tires now want to spin at the same speed no matter which way the wheel is pointed. The rig wants to go straight, and tight corrections get harder.

That is the reason to line up first and lock second. Trying to steer into position with the front locked usually means backing up and starting over.

Do not leave them on

Treat lockers as a tool for a specific obstacle, not a setting for the whole trail. Running locked all day means fighting the steering on every turn, scrubbing tires through corners, and putting steady load into axle shafts and u-joints that they do not need.

Locked axles on dry pavement are worse. There is nowhere for the difference in wheel speed to go, so the driveline binds and something eventually gives. Unlock before you air up and head home.

If a locker does not drop out when you flip the switch, roll straight for a few feet with light throttle. That unloads the diff and lets it release.

Around Summit County that plays out on climbs like Saints John and Peru Creek, where the traction problem shows up in short sections rather than across the whole route. Lock for the ledge, unlock for the road between them.

Knowing when to use lockers changes what your rig is capable of and turns hard obstacles into manageable ones.

Until next time, enjoy the trail! Scott

Common questions