how to tell if you have posi traction

[ckomai]

Is there a way you can see if you have a limited slip differential without jacking it up and testing it? I heard you can check the axle specs on the side of the drivers door and if it has a D4 then you have it. Is this true?

 

[swshawaii]

True, unless it's been replaced. Should also be a tag on the differential cover.

http://www.explorerforum.com/ntrprize/Axle.htm

Wikipedia:

A slang term for a limited-slip differential is Posi, named after GM's "Posi-Traction" unit which was built by Eaton.[1]

 

[ckomai]

got it, i have open diff with 3.55 gears. Thanks

 

[Mettler]

Yes the D4 axle code on the door tag means you have the trac lock differential that ford has been using in cars like the torino cobra jet and mustangs. I love this rear end. Im glad mine came with it. Its enough for my uses.