Does this look like a posi?

[Gyawo]

A posi and a limited slip are the same thing, just a name that GM came up with. Here are what some other manufacturers call them:

* Alfa Romeo: Q2
* American Motors: Twin-Grip
* Buick: Positive Traction
* Chevrolet/GMC trucks (after 1973): Gov-Lock and Positraction
* Chrysler: Sure Grip
* Dana Corporation:Trak-Lok or Powr-Lok
* Ferrari: E-Diff
* Fiat: Viscodrive
* Ford: Equa-Lock and Traction-Lok
* International: Trak-Lok or Powr-Lok
* Jeep: Trac-Lok (clutch-type mechanical), Tru-Lok (gear-type mechanical), and Vari-Lok (gerotor pump)
* Oldsmobile: Anti-Spin
* Pontiac: Safe-T-Track
* Porsche: PSD (electro-hydraulic mechanical)
* Saab: Saab XWD eLSD
* Studebaker-Packard Corporation: Twin Traction
* TVR: Hydratrak

To answer your question as to if it is worn out or it that is just how it works I am not too sure, not too familiar with how they work. I have only ever had an open rear end in my trucks. Just know what they look like.