Ever find yourself wondering if you should get a limited slip or locking differential for your next vehicle? Whether you’re looking for better performance, improved off-road capability, or safer winter driving, your choice of differential makes a huge impact.
Let’s look at the differences between these two systems so that you can make the right choice based on your vehicle and driving style.
What is a Differential?
Before getting into limited slip and locking differentials, it’s helpful to understand how a basic differential works. A differential is a mechanical device that splits engine power between two wheels while allowing them to rotate at different speeds.
This speed difference is necessary because your vehicle’s outer wheels need to spin faster than the inner wheels during turns. Without a differential, the wheels would fight against each other, making turning difficult and causing excessive tire wear.
Related: Types of Drivetrains (Comparison)
How Does an Open Differential Work?
An open differential is the most basic and common type found in most vehicles. It uses a set of gears to distribute power equally between two wheels. When both wheels have equal traction, the power split is 50/50.
While it may sound logical, there’s one huge drawback with open diffs: when one wheel loses traction, the differential sends most of the power to that spinning wheel. This is why you might see one wheel spinning in snow or mud while the other wheel (which has better traction) stays still.
This behavior makes open differentials less than ideal for:
- Slippery conditions (snow, ice, or rain)
- Off-road driving where one wheel might lift off the ground
- Performance driving where power is needed through corners
- Launching the vehicle quickly from a stop
Limited Slip Differential (LSD)
A limited slip differential (LSD) helps solve the main problem of open differentials by restricting power transfer to a spinning wheel. When one wheel starts to slip, the LSD transfers more power to the wheel with better traction, helping you maintain forward momentum.
See Also: How a Limited Slip Differential Works
Types of Limited Slip Differentials
Clutch-Type LSD
The most common type uses a set of clutch plates to transfer power between wheels. When one wheel spins faster than the other, these clutches engage and force both wheels to rotate at more similar speeds.
These LSDs work well for both street and track use but require periodic maintenance as the clutches wear.
Gear-Type LSD
Also called helical LSDs, these use special gears instead of clutches to transfer power. They’re more durable than clutch-type LSDs since they have no friction materials to wear out. However, they typically cost more and can’t be adjusted like clutch-type LSDs can.
Torsen LSD
Short for “torque sensing,” Torsen differentials use worm gears to direct power to the wheel with more traction. They respond instantly to traction changes and don’t wear like clutch-type LSDs.
However, they need at least some traction on both wheels to work – if one wheel is completely off the ground, a Torsen LSD acts like an open differential.
Advantages of Limited Slip Differentials
- Better traction in slippery conditions
- Improved acceleration out of corners
- More predictable handling
- Good for daily driving
- Works automatically without driver input
Disadvantages
- More expensive than open differentials
- May require periodic maintenance
- Can wear out over time
- Some types make noise during low-speed turns
- Not as effective as lockers for serious off-road use
Locking Differential
A locking differential (or “locker”) is the most aggressive solution to the open differential’s limitations. When engaged, it physically locks both wheels together, forcing them to spin at exactly the same speed. This provides maximum traction since both wheels receive equal power regardless of available grip.
Types of Locking Differentials
Automatic Lockers
These lock and unlock on their own based on driving conditions. When you’re driving straight, both wheels are locked together. During turns, they unlock to allow different wheel speeds. While simple and effective, they can be noisy and cause unpredictable handling on paved roads.
Selectable Lockers
These give you control over when the differential locks. You can leave it unlocked for normal street driving and engage the locker when needed for off-road situations. Activation methods include:
- Electronic switches (most common in newer vehicles)
- Air pressure systems
- Cable-operated mechanisms
Mechanical Lockers
Sometimes called lunchbox lockers, these replace only the internal parts of your existing differential. They’re a cheaper option but tend to be noisier and less refined than complete locker assemblies.
Advantages of Locking Differentials
- Maximum traction in extreme conditions
- Perfect for serious off-road use
- More durable than limited slip differentials
- Less maintenance than LSDs
- Great for rock crawling and deep mud
Disadvantages
- Can make steering difficult when engaged
- Not ideal for daily street driving
- May cause tire wear if used on pavement
- Usually noisier than other differential types
- More expensive than LSDs in most cases
Common Applications
Let’s look at which differential type works best for different vehicles and driving styles.
Daily Driver/Street Use
For most daily drivers, a limited slip differential is the best choice. It provides extra traction when needed while behaving like a normal differential during regular driving. Clutch-type or Torsen LSDs are particularly good for street cars since they operate smoothly and don’t affect normal handling.
Performance/Track Use
Performance cars often benefit from limited slip differentials. They help put power down when accelerating out of corners and improve stability under hard driving. Many sports cars come with LSDs from the factory, but aftermarket units can provide even better performance. Torsen and clutch-type LSDs are popular choices here.
Off-Road Use
The choice between LSD and locker depends on your off-road style:
- For trail riding and moderate off-roading, an LSD might be enough
- For rock crawling or serious off-road use, a selectable locker is best
- For dedicated off-road vehicles, automatic lockers work well
Truck Applications
Many trucks use different setups front and rear:
- Front: Usually open differential or selectable locker
- Rear: LSD or selectable locker depending on use
- Heavy duty trucks often offer factory locker options
Winter Driving
A limited slip differential usually works best for winter conditions. It provides extra traction without the harshness of a locker, and it works automatically when you need it. Plus, you won’t have to worry about engaging or disengaging it as road conditions change.
Maintenance and Cost
Keeping your differential working properly depends on which type you have. Here’s what you should know about maintaining each type and what they typically cost.
Basic Differential Maintenance
All differentials need regular fluid changes:
- Change differential fluid every 30,000-60,000 miles
- More frequently if you tow or drive off-road
- Check fluid level and condition during regular service appointments
- Look for metal particles in old fluid
- Differential fluid change cost is $80-150 at a shop
Limited Slip Differential Maintenance
- Requires special friction-modifying oil additives
- Clutch-type LSDs need fluid changes every 30,000-60,000 miles
- May need clutch replacement after 100,000+ miles
- Listen for chattering noises during turns
- Costs $800-1,500 for a new unit plus installation
Locking Differential Maintenance
- Uses standard gear oil without additives
- Service intervals match regular differential maintenance
- Check actuator operation (electronic/air systems)
- Watch for unusual noises or engagement issues
- Costs $1,000-2,000 for a new unit plus installation
Installation Costs
Labor costs vary significantly based on your vehicle and differential type:
- LSD installation: 2-3 hours ($200-400)
- Locker installation: 3-5 hours ($300-500)
- Additional costs if axle setup is needed
See Also: Differential Repair Cost
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Who engages lockers on a paved road?
You wouldn’t want to do engage a locker on a paved road, unless that paved road had a lot of ice or snow and you needed to get yourself unstuck.
Would lockers let you retain control if a tire went off the road into deep mud in a serious rain? Or would limited slip be a better fit? Assuming we’re talking RWDs, which axle would you want sporting that?
I lost a FWD Toyota sedan a couple years back when it understeered on a mild turn, my front passenger tire drifted into the mud, and both steering and control were gone.
It pulled a couple spins until
the driver’s side slammed into a farm fence (and my head was smashed through my side window). Concussion took 6 months to heal from. And those were pretty standard road conditions for half the year around here, so I’m looking for a truck (that I can afford to write off if it’s trashed, so probably a mid-2000s Chevy Silverado) with which I could’ve kept power and steering in that same situation.
The biggest factor in how much control over the vehicle you have is your tire choice, not the differentials. If you were understeering, your front tires gave up grip for some reason.
Fancy differentials may help reduce understeer or oversteer on power, but they often don’t help off throttle and under braking. Fancy differentials are not an adequate substitute for running the correct tire for the conditions, no matter which wheels receive torque from the engine.
A rear wheel drive vehicle only has one differential, and it sits between the rear axles.
Buy the highest quality tires you can afford for the conditions you plan to drive in. Make sure you don’t drive too fast for the conditions, and it wouldn’t hurt to take a high performance driver’s education (HPDE) course for more experience driving at the limit under controlled conditions on a closed course.