If you have ever been out in your Jeep JK in bad weather conditions and found that you have hit the gas and one wheel is spinning freely while the other does nothing, you will have been incredibly frustrated no doubt.
This is down to the open differential that your Jeep was fitted with on the production line.
It’s a necessity for daily driving as it allows tires on the same axle to rotate at different speeds when taking a corner. Yet it is not so great when you need to get out of a ditch or through some snow or even if you’re trying to tow someone else.
What you need is a wheel locker, something that does exactly as it says. Locks the wheels to move at the same speed with the same amount of power. This gives your Jeep super traction to power on through that mud.
For the weekend mechanic and car enthusiast, these are a relatively simple installation that takes a few hours of your time and a little know-how, or a handy YouTube video!
Take a look through our guide, we have hand-picked 10 of the best lockers for Jeep JK available at the moment.
We have researched and reviewed them to help you make the most informed buying decision.
Comparison Table of 10 Best Lockers for Jeep JK
1. USA Standard Gear SL D30-27
Mechanical locker/ differential-27 axles Spartan Locker for Dana 30 Differential 27 Spline
If you’re looking for a lunchbox locker, so-called because it is compact and easy to fit, consider this one from USA Standard Gear.
This locker will give you 100% traction all of the time making it ideal for off-road and trail enthusiasts.
With couplers and drivers fabricated from highest grade 9310 steel, it will have a long service life due to its superb strength and durability.
It has a unique pin design ruling out the need for thrust washers, this makes it much easier to install. It will fit simply into the existing differential case, replacing the stock spider gears.
It is compatible with both 27 and 30 splines. Each tooth has been precision-cut and ultra-heat treated to give you the superb traction and ratchet noise you desire.
Drop this into your truck and the most rugged terrain will become easy to master.
2. Eaton 913A481 Detroit Truetrac 8.5" 30
Selectable electronic locker
Locking, Ring Gear Dia. 8.6", 30-Spline, Axle Shaft Dia. 1.31"
If you like the idea of having fantastic handling when you’re doing your everyday driving, but then having extreme traction when faced with an obstacle, then seriously consider this locker from Eaton.
It is a selectable differential locker which means by flicking a switch installed on your dash, you can go from highway driving to challenging terrains such as rocks or deep ditches. One further flick and it opens the wheels back up again, giving you a quiet ride and smooth cornering.
It works via an electromagnetic mechanism and helical gears, once activated 100% of the torque that is available will be transferred equally to both wheels. This can be either the front or rear wheels as this model is available for both.
This aggressive traction works just as well in reverse as it does when driving forwards.
The locker itself has net-forged gears, giving maximum strength and long-lasting durability.
Fitting is relatively simple, there are some fantastic easy-to-follow YouTube videos that show you step-by-step.
3. Yukon Gear YDGGM8.5-3-30-1 GM 8.5"/8.6"
GM ring gear 8.5"/8.6" - 30 Spline Axle Dura Grip
Limited Slip Positraction
Yukon Gear and Axle is a trusted brand name in the differential industry. All of their components are made in the USA and are put to the most stringent tests.
Knowing that and the added fact that this locker has internal components forged from 4320 steel inside an iron case, should guarantee you that this locker has strength and resilience at its heart.
The clutch-style positraction allows the friction plates to slip a little at corners, allowing a much smoother ride. In fact, everything about this locker says smooth, the 4-spring design makes transfers between off and on-road driving barely noticeable.
The traction quality on both wheels is superb, it’s very aggressive and can handle rocky trails with ease.
This really is a top-quality performance modifying product.
4. Aussie Locker XD-13027 for Dana 30 7.2-Inch 27
Dana 30 7.2-Inch 27 Axle Spline Locker
The name of this locker might have you think otherwise, but the Aussie Locker is made in the USA.
It has been designed to simply replace the existing spider gears in an open differential carrier. You should be able to use the pre-existing spider thrust washers as like-for-like too.
The installation is so simple enough for the car enthusiast to do at home. Aussie Locker suggests that anyone proficient enough to change a set of brakes can easily manage this job.
It is built from such high-quality steel that it won’t suffer from degradation for a very time.
There is nothing about this product that can break, leak or fail, no wires, cables or pipes.
This really is an advanced locker, it will give you 100% traction performance in comparison with other style lockers that only give you a 40/60 share of the available torque.
5. USA Standard Gear (SL D44-30) Spartan Locker
Dana 44 Differential with 30 Spline Axles
As with the previous Sparten Locker we reviewed, this is the “lunchbox” style. Compact and easy to install, it simply drops into the stock open differential carrier case without the need to remove it from the axle.
There is no use for thrust washers due to the unique spring and pin design.
The perfectly cut teeth have been treated at exceptionally high temperatures to allow them to ratchet together for a long time ahead. The 9310 steel fabrication also contributes to this durable, long service life.
You will barely notice a difference when daily driving, though if the locker has been installed on the front axle your first few tight corners may feel a little different. Installed on the rear axle and you’ll feel no difference at all.
These may be budget price lockers but they really do provide top-quality traction, the performance improvement over factory fitted differentials will have you amazed.
6. Detroit Locker 913A481 Trutrac Differential with 30 Spline
Limited Slip Differential
30 Spline for GM 8.5/8.6", 10 Bolt Rear End
Detroit Locker has long been a name that means reliability and quality within the auto-part industry.
This limited slip locker maintains the smooth driving capabilities of your Jeep when the road surface throws up no issues. As soon as the terrain proves challenging and a loss of traction is sensed then the locker springs into action. Forces created by gear separation deliver 100% torque to the wheel with the most traction. This will cause it to dramatically slow down until it stops, thus giving you incredible grip and power to get moving again in harshest conditions and terrains.
This is such a powerful and durable piece of kit that professionals and off-road fanatics rely on it for competitions and many seriously rugged trail adventures.
Here is absolutely no need to flick a switch to activate the lockers, the helical gears automatically mesh together when force is needed and engage automatically. They react quickly and smoothly.
Whether you’re driving on a flat road or a rocky trail you can guarantee a smooth, quiet drive with superb handling.
7. USA Standard Gear (SL C8.25-29) Spartan Locker
Fits Chrysler 8.25” with 29 splines
This mechanical Sparten locker from USA Standard Gear has been designed to give you a tough, robust off-road performance, with hugely increased strength and power over any stock differential.
The locker itself is made from strong 9310 steel and as such, it will be durable and reliable. The teeth have been precision cut, this also adds to the life expectancy.
The compact lunchbox design allows for easy installation. Simply drop it into the existing open carrier case, in place of the now redundant spider gears. The unique spring and pin system helps make the installation go without a hitch.
This automatic device offers 100% traction to both wheels when driving in a straight line, but possesses the ability to ratchet back to allow cornering without any slipping.
This action is what causes the clicking sound consumers sometimes say they can hear when driving around bends.
This noise doesn’t always feature, when it does it is surely a small price to pay for such a competitively priced, high-quality and powerful product.
8. Detroit Locker 912A585 Trutrac Differential
Limited slip differential
27 Spline for Dana 30, 3.73 and higher gear ratios
Another offering from Detroit Locker, this time to be installed on the front Dana 30 axle.
It’s another slip differential meaning it isn’t a true 100% locker until the time is right.
It will allow your Jeep to have the same great handling that you’ve always been used to, when out on the highway. The second it encounters some loss of traction, whether it be ice, mud or rough terrain, the differential comes into its own.
It will automatically kick in, sending 100% torque to the wheel with most traction, allowing the vehicle to charge through or over any surface.
So while this isn’t a straight forward locker, it combines the best of both worlds, the handling of an open differential with the all-out power and grip of a mechanical locker.
It really is hard-core and aggressive, rock shelves, tree trunks, and deep muddy ditches will no longer stand in your way.
Helical gears provide the power, they also ensure your ride will remain smooth and that those automatic changes will barely be noticeable.
Tough and durable, maintenance-free and reliable, whether your driving to work or on a rugged trail.
9. Powertrax 2210-LR Lock-Right (Dana 30)
to fit Dana 30, 27 spline
If you are really serious about off-roading and demand the most a locker can offer then you should seriously consider this LR locker from Powertrax.
It is constructed from zytanium strength alloy to feel virtually indestructible. It will provide the maximum traction that your vehicle can expect, whether that be in the harshest off-road conditions or the most severe on-road situations.
It is a lunchbox style locker so will drop-in existing case assemblies without the need for any specialist tools. It will replace the existing spider gears.
Powertrax specializes in extreme traction solutions so you can expect a hard-wearing, tough and reliable piece of kit that gives much-added strength to your vehicle in many applications.
Wheel speeds need to rotate at different speeds to make cornering smooth, that’s how an open differential works. This locker very cleverly allows internal gears to run across each other when you approach bends. You may hear a slight ratcheting sound, but this is totally normal and is a tiny price to pay for such high-quality traction.
10. Sylvan Reinforced Automotive Climb Master Differential Locker
Limited slip differential
Dana 30 27 splines
This Sylvan locker is a lunchbox style, it is compact and easy to fit. It will drop into the existing open carrier housing of your Jeep and should take no more than 3 or 4 hours to complete the job.
It is constructed from hard steel making it durable and strong, this also gives the locker a long service life as corrosion will be kept at bay. It has recently undergone stringent testing and the design has been further upgraded, to prevent any cracking that might occur from the heat treatment. It is now reinforced to make it tougher than ever.
This product will make your vehicle safer for you, no unnecessary accident or slips, it will give you smooth road handling and superb traction to reach the summit of your choice.
You will have confidence in your vehicle, no matter what the conditions, and all for excellent value, some might say, budget, cost.
Why choose a locker for a Jeep JK?
Let us bring this right down to basics, any vehicle has 2 sets of wheels, either end of an axle. These wheels are allowed to spin independently of each other as when a vehicle drives around a bend, the outer wheel obviously has to cover a large space than the inner wheel. It will need to spin faster.
By adding a locker to the axle, both wheels on the same axle will be ‘locked’ and made to move at exactly the same rate with the same force. This will give the vehicle increased traction as the power will give all available torque to the wheels.
This will help the Jeep overcome its limitations, whether it’s a muddy ditch or slippery slope in regular driving or if you have an adventurous side and decide to hit the trail for some serious off-roading fun.
Let’s talk differentials
This is the mechanism that allows your wheels to spin at different speeds. That is it. It is found on the axle and is particularly suited to helping your vehicle drive smoothly around a bend. The restriction that a locker might supply makes cornering very awkward, both tires rotate at the same speed, making the action jerky and the tires hop, causing unnecessary wear and tear to the tires.
When choosing which is the best locker for your Jeep JK, you will be met with a series of numbers, criteria to match up to, let us try and Jargon Bust for you,
Dana 30, Dana 44, etc. This is the usual axle that will be fitted in your Jeep as stock. The number equates to its size and ability. Finding the type you have is usually simple, a tag will be bolted on or the numbers will be embedded into the differential carrier itself. If this has worn off over time and you can’t recognize the axle by sight, simple comparisons can be made online to match its shape, number of bolts, etc.
Splines: Just another name for the teeth on the locker that need to mesh together to provide the torque needed to slow the wheel with the most traction.
Spider gears: These are the gears that direct the power to the axle shafts. The differential pin holds them in place, ensuring that the power is equally divided between the 2 wheels on that axle.
Gear ratio: This is worked out by dividing the number of teeth on the ring gear by the number of teeth in the pinion gear.
This is how to find out how many times the drive shaft (pinion) will need to rotate to turn the wheels one full rotation.
For example a ratio of 3.52:1 means that the drive shaft will need to spin 3.52 times for the wheels to turn once.
Greater traction comes with lower gear ratios.
Types of differentials and lockers
This is usually what your Jeep will have, what was fitted in the factory.
Wheels on 1 axle will need to be able to rotate at different speeds when cornering, this limits wear and tear on your tires. A tire worn low will obviously have significantly reduced traction.
Off-road driving is a virtual impossibility as 1 tire will have more traction than the other, it will just spin as the other offers nothing.
This type of locker seems to offer the best of both worlds. It behaves as an open locker would until it encounters a surface that requires greater traction, usually mud or snow.
In these circumstances, the locker will recognize the difference in traction and send power, torque, to the wheel to give an even, and greater traction to combat the obstacle.
This is done via a pressure device, clutch pack or helical gears.
A limited slip differential provides great traction in bad conditions whilst also have great on-road handling characteristics.
This is a 100% traction device that locks both wheels to give the most powerful traction for rock-crawling, drag racing, and extreme off-roading.
There are 2 varieties, firstly the full spool, this is in place of the entire ring gear carrier. Secondly, the mini spool, or lunchbox locker as its known. It is easier to install as it drops neatly inside the Jeep’s stock carrier case, in place of the spider gears.
Although not recommended for daily use, there is a way to overcome this by using a selectable locker.
This is where a manual switch is fitted to the dash that you activate when you need to bounce between locked and unlocked traction.
It is usually the more expensive of the 2 options but gives greater on-highway handling once your off-road adventure is over. It is also more difficult to install.
The other choice is an automatic locker. This is the cheaper option and is also easier to fit.
On-road handling isn’t as good as it could be and you may notice differences when taking bends. You may hear the ratchet clicking away and fell some tire skip too.
But as an off-road preference, this really is a beast. There are very few surfaces that this locker won’t help your Jeep to conquer.
Also read: 10 Best Ball Joints for Jeep JK Review
Where will you be using your Jeep?
Not all lockers are the same, when looking to purchase one you should take many variables into consideration, mainly where will you spend most of your driving time in the Jeep?
You may need it for work purposes on agricultural or industrial land or whether you just live out in the sticks and need something reliable for when the conditions are bad.
Maybe off-roading is your passion and you need an all-round aggressive Jeep with superb traction that fears nothing, not even the most extreme terrain.
As with all car components, there can be a huge difference in pricing. The most expensive may not necessarily be the best, and likewise, the cheapest locker may not be the worst.
Set a budget and try and stay within it. Our review has found the best locker for Jeep JK across a wide range of budgets.
Maybe you are drawn to a certain brand as you have had previous success, or had a recommendation.
You will want a locker that is solid and durable. It is quite a hefty after-sales expense that you will be making, you need to know that it is going to last.
Look for a locker that requires minimal maintenance, if any at all. One that is robust and will not degrade over passing months. All of the products featured in our review fit this criterion.
Easy to install?
If you’re a competent mechanic and are going to attempt the installation yourself, knowing that the instructions are accurate and that the install is straightforward is a big help.
We have found that the lunchbox style locker seems to be the most simple to fit, less time in the garage means more in the Jeep!
Also read: Best Shock Absorbers for Light Trucks
Front or rear installation?
This is a tough question as it’s often down to personal choice.
For serious off-roaders, the most hardcore ones amongst you who enter competitions and climb rock faces for fun, then the simple answer is, both!
You are obviously going to get the most extreme traction and ultra power if all 4 wheels lock.
Installing on the rear axle of a 4WD would usually be our choice, traction improvement would be beyond amazing.
When fitting to the front axle issues might arise. Steering and power delivery comes via the front axle, sending that power to both wheels equally will make them tough to turn, this is called torque steer. Added stress to your components can shorten their life expectancy.
Limited slip differentials are a game changer, as they can handle limited traction areas.
Also read: Best Spark Plug Wires for Performance
We have assembled this guide of the best lockers for Jeep JK to help you make the most informed choice possible.
Ensure the specifications of the locker that you decide on are suitable for your Jeep if not, that manufacturer will probably be able to offer you a very close alternative. Check on the sales page, there will always be a space to enter the make, model and year of your Jeep to make sure you get the right piece of kit.
When your locker has been fitted, we wish you many successful off-road adventures, dropping to lower speeds, gripping that terrain with mighty traction and climbing out of or over the toughest obstacles.