Limited Slip Differential Upgrade Guide for the Challenger
The Challenger's rear differential is one of the most important components for putting power down. Here's what your car came with, when an LSD upgrade makes sense, and what the best options are.
What Came Stock
R/T and Scat Pack models: Factory open differential or Electronically Controlled Limited Slip Differential (eLSD) depending on options/model year. The eLSD uses clutch packs controlled by the stability control system.
Scat Pack with Performance Axle Group: Standard Clutch-Type LSD — a mechanical limited slip that distributes torque between rear wheels.
Hellcat: Factory Torque Reserve Management system with eLSD.
An open differential sends torque to the wheel with least resistance — on a powerful car, one wheel spins freely while the other gets nothing. A limited slip distributes torque to both wheels, dramatically improving traction on launches and out of corners.
Types of Limited Slip Differentials
Clutch-type LSD (factory SRT units): Uses friction clutch packs to create a mechanical coupling between wheels. Requires periodic fluid changes with friction modifier additive. Effective, proven technology.
Helical/Torsen LSD: Uses gear geometry to create torque-biasing. No clutch packs to wear. Smoother operation. Cannot achieve locking ratios as high as clutch-type.
Locking/Spool: Mechanically locks both rear wheels together permanently. Maximum traction at straight-line launch. Zero cornering ability — the outside tire must skid in any turn. Drag-only application.
Eaton Posi/TrueTrac: The Eaton TrueTrac is a worm-gear torsen-style unit that many Challenger owners use as an upgrade or replacement. Very smooth, no clutch packs to service.
When to Upgrade
You have an open diff: If your R/T or earlier Scat Pack has an open differential, installing any LSD is a dramatic improvement. Single-wheel burnouts become two-wheel traction. Launch performance improves significantly.
Your factory LSD clutches are worn: If you do regular drag launches, the clutch packs in a factory LSD wear out over time. Symptoms: one tire spinning more than the other in launches, reduced traction in wet corners. Rebuild or replace.
Building for drag: A spool or high-preload clutch LSD maximizes straight-line traction at the cost of cornering behavior.
Recommended Upgrades
Street/Strip:
- Eaton TrueTrac: Most recommended for street/strip builds. Smooth, durable, no clutch pack maintenance. ~$350–$500 installed in the diff housing.
- Yukon Grizzly Locker (selectable): Can operate in open mode for normal driving and lock on demand. Complex but versatile.
Dedicated Drag:
- Detroit Locker: Ratcheting style, locks hard on acceleration, unlocks for cornering. Good strip performance with acceptable street manners. ~$400–$600.
- Full Spool: For full drag builds only — remove and replace when switching between events if the car also gets driven on the street.
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