Locker & LSD Reference

Every differential type explained — how it works, what it's best for, and which brands to look for.

Open Differential

OPEN
Stock

Always sends power to the wheel with least resistance. When one wheel lifts, all power goes there.

Street

Trail

Crawl

Best for:Normal street driving. Factory standard on most vehicles.
Drawbacks:Zero off-road traction when one wheel loses contact. Useless in mud or on rock.
Brands:Factory OEM

Clutch-Pack LSD

LSD
$300–$700

Clutch discs engage under torque and wheel speed difference, transferring power to the slower (gripping) wheel.

Street

Trail

Crawl

Best for:Daily drivers, light off-road, performance street cars. Smooth, progressive engagement.
Drawbacks:Clutches wear over time and need rebuild or additive. Engagement fades when hot.
Brands:Auburn Gear, EATON Posi, Ford Traction-Lok, GM G80

Torsen / Helical Gear LSD

LSD
$400–$900

Worm gears bind under torque differential, sending power to the wheel with more grip. No clutches to wear out.

Street

Trail

Crawl

Best for:Performance street, light trail. Self-cleaning, maintenance-free. Very smooth on-road.
Drawbacks:No locking at zero grip — if a wheel lifts completely, torque goes to it. Not for serious crawling.
Brands:Torsen, Wavetrac, Quaife, Eaton Truetrac

Lunchbox Locker

LOCKER
$150–$350

Replaces spider gears inside the stock open carrier. Locks fully like a spool but releases in corners.

Street

Trail

Crawl

Best for:Budget-friendly upgrade for light trail and crawling. Installs in factory housing — no ring/pinion swap.
Drawbacks:Clunky on pavement — clicks and pops in turns. Not ideal for daily driving. Steering can be affected on front axles.
Brands:Detroit Lock-Right, Spartan Locker, PowerTrax No-Slip

Detroit Locker (Auto-Lock)

LOCKER
$500–$900

Ratchet mechanism locks both wheels under power. Releases and ratchets during cornering. Aggressive and reliable.

Street

Trail

Crawl

Best for:Serious trail trucks and dedicated off-road rigs. Extremely durable in heavy-duty applications.
Drawbacks:Harsh snap and clunk on pavement. Oversteer tendency on loose surfaces. Front axle use discouraged for street.
Brands:Detroit Locker (Eaton), OX Locker (rear)

Selectable — Air Locker (ARB)

LOCKER
$600–$1,000 + air system

Compressed air engages a sliding collar to fully lock the differential on demand via a dash switch.

Street

Trail

Crawl

Best for:Best of both worlds: open on street, fully locked on trail. Ideal for any serious off-road truck.
Drawbacks:Requires on-board air system (or ARB compressor kit). Higher cost. Air line routing adds complexity.
Brands:ARB Air Locker

Selectable — Electric Locker

LOCKER
$400–$900

Electric solenoid or motor engages a locking collar on demand via a dash switch. No air system required.

Street

Trail

Crawl

Best for:Great daily/trail balance. Easier installation than air lockers. Factory option on many 4x4s.
Drawbacks:Engagement can be slower or less positive than air. Some designs have limited max torque.
Brands:Toyota eLocker, OX Locker, Warn, Auburn ECTED

Spool / Mini-Spool

Spool
$50–$300

Eliminates the differential entirely — both axle shafts spin at the same rate at all times.

Street

Trail

Crawl

Best for:Dedicated crawlers, drag cars, rock race vehicles. Maximum traction always.
Drawbacks:Destroys tires and driveline on pavement — understeers severely in turns. Never for street use.
Brands:Strange, Yukon, G2, Moser

Choosing the Right Differential

• Daily driver + occasional trail: Selectable electric locker or clutch-pack LSD — normal on street, locked when needed.

• Dedicated trail rig: ARB air lockers front and rear — the gold standard for serious off-road builds.

• Budget trail build: Lunchbox locker in the rear only — cheap upgrade with significant improvement.

• Pure rock crawler: Detroit Lockers or spools with a dedicated no-street trail rig.

• Always check axle spline count and ring gear size compatibility before purchasing.