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Locker Vs. Limited-Slip

Which One Is Better?

By , Photography by Courtesy Of Eaton,
Truetrac Limited Slip Differential Detroit Locker Detroit Truetrac

Now that we've sucked you in with that title, we'll tell you right now that it's not a matter of which differential is better, it's a matter of which one is better for you!

Limited-slip differentials and locking differentials are both added to axles in an effort to achieve more traction in environments where one wheel can break traction and spin, leaving a vehicle with an open differential doing what's known as a peg-leg dance. Without having a limited-slip or locking differential in an axle, you can lose forward motion when one wheel breaks traction and spins, leaving the other one (wheel) to sit idle. Having a traction-aiding diff instead of an open diff not only helps in the dirt, but on pavement as well. In fact, we prefer something other than an open differential in any truck, SUV, or car that we drive.

It's about this time that you're probably asking yourself, "Why wouldn't I completely lock both axles together full time with a spool or something?" And this is an excellent question. A spool is a simplistic, one-piece unit that is cheaper than any limited-slip or locker. It's also stronger, lighter, and has no internal parts to service (and is technically not a differential). The problem is that wheel speed (from side to side) differentiates when turning. A spool is fine for something like a drag car that does all of its forward motion in a straight line, but most vehicles need to turn left and right. When a vehicle turns, the inside (of the turn) wheels spin more slowly than the outside wheels. Without some type of axle differential that allows wheel speed differentiation, the vehicle will be pushed straight forward and the inside driven tire will chirp as it skips along.

This is why a limited-slip or locking differential is much preferred over a spool in a street-legal application. But which one (limited-slip or locker) is better for you? That's really a question of application.

  • The Detroit Locker is an automatically-locking differential that was originally introduced in the early '40s as the "No-SPIN" differential. An automatic locker is one that locks both axleshafts together automatically when forward or reverse torque is applied to it. The Detroit Locker is designed to stay open otherwise, allowing wheel speed differentiation for normal driving. It doesn't engage until you accelerate, basically. The two most common complaints with an auto locker is that they engage and push the vehicle straight when accelerating out of a turn, and that they (harmlessly) clunk or bang occasionally-sometimes so loudly that you'll believe an axleshaft has broken.
    The Detroit Locker is an automatically-locking differential that was originally introduced
  • The Detroit Locker allows wheel speed differentiation when torque is not applied to it. Pictured is the clutch assembly and side gears that allow the automatic locker to switch from "open" to "locked" when torque is applied.
    The Detroit Locker allows wheel speed differentiation when torque is not applied to it. Pi
  • In this application, a locker is necessary to achieve the driving routes this Bronco owner has chosen. When making climbs such as this, vehicle weight can be biased to one side and a tire can lift off the ground. If a tire lifts off the ground in this extreme scenario, only a locking differential will allow the touching tire to propel the vehicle forward. A limited-slip differential would likely not be effective enough to move the vehicle once a tire goes airborne.
    In this application, a locker is necessary to achieve the driving routes this Bronco owner

Advantages of a Locking Differential
• True two-wheel drive per axle
• No servicing
• Extremely durable
• Bolt-in applications with zero axle, ring-and-pinion, or axleshaft modification
• Greatly enhances traction

Cons of a Locking Differential
• Wears tires out more quickly
• Front locker makes steering difficult
• Occasional banging/clunking of automatic lockers could give your grandma a heart attack
• Can make snow/ice driving more difficult

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