What kind of diff is this?

The guy I bought it from said it has a detroit locker, but when I opened it up I was greeted with this. It has 31 spline axles with c-clip eliminators too. Is that an eaton posi or what???

DSC03646.webp

DSC03645.webp

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These are the pics I have found of the eaton posi.

Posi-SM.jpg


posi-exploded-573.jpg


It looks pretty much exactly the same but on mine there are 3 springs on the one side and in that blown up picture it only looks like there are two. I cant find a picture of that side of the diff when It is all assembled.
 
Well, depending on which differential/rear-end specialist you talk to, rebuilding any differential is completely hit and miss as to the results/longevity no matter how carefully you do it even with the best parts.

If it is in good shape, I too would be quite content to discover an Auburn unit in my car.