Trac lock

I've had a Trac Loc with 3.55 gears in the 8.25 in my 70 Duster for several years now. It's a good light duty LSD for street use, especially when cost is a consideration. It is completely transparent in operation and you'll never even know it's there until you call upon it to leave a couple of black stripes on the pavement. If you're going with a used unit, you'll need to verify the axle spline count, the later units, mostly after 97 are 29 spline and all of the earlier ones are 27.