I have a chance to buy what the seller describes as a posi unit from a Dana 44 front. He said it came from a '73 blazer. You can see that the ring gear is chipped in one of the pictures, but that is not what I'm concerned about I can replace those. I'm interested in the posi. I thought a posi unit would have plates and springs in it. Is this some kind of gov-lock or some other kind of posi unit. It seems to have clutches in it. Info please??