8.25 Lockers (ARB, Detroit Truetrac, Powertrax)

Difficulty 4/54–14 hrs$300–15001997-2001

The 8.25 supports ARB selectable lockers, Detroit Truetrac LSD, and Powertrax lunchbox options. Detroit Truetrac is the popular daily-driver-friendly choice.

Locker options for the Chrysler 8.25:

ARB Air Locker:

RD117 (27-spline 3.55 and down) and RD118 (29-spline) — selectable, premium, ~$850.
Excellent for daily drivers who want full lock on demand.

Detroit Truetrac:

27-spline ~$520, 29-spline ~$580. A torque-biasing limited slip — not a full locker. Always engaged but acts like an open diff in turns. Most daily-driver-friendly.

Powertrax Lock-Right or Aussie:

27-spline ~$300. Automatic locker, drops into stock carrier. Same caveats as D35 lunchbox.

For a daily-driven XJ with the 8.25, the Detroit Truetrac is the most popular choice — never have to think about it, works in mud/snow/light off-road, no on-road quirks. For dedicated trail use, ARB Air Locker is the top choice.

Install: ARB requires full diff setup (8-14 hours). Lunchbox is ~4 hours. Truetrac is similar to lunchbox (drops into stock carrier) but requires verifying the right spline count.

Why it works

Multiple locker options
Truetrac is daily-driver-friendly
ARB is best for selectable use

Trade-offs

Less aftermarket than D44/8.8
29-spline lockers limited availability

Tools required

metric sockets
torque wrench
differential setup tools (ARB)
drill (ARB)

Parts

Part	Vendor	Est. price
ARB Air Locker 8.25 27-spline	ARB	~$850
Detroit Truetrac 8.25 27-spline	Eaton / Detroit	~$520
Powertrax Lock-Right 8.25 27-spline	Powertrax	~$300

Sources

{'title': 'Eaton Detroit Truetrac 8.25', 'url': 'https://www.eaton.com/us/en-us/products/differentials-traction-control/detroit-truetrac.html'}

Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.