Hey, there is nothing wrong with the occasional bath in various oils/fluids. Keeps the hair shiny! Anyway, if you want to swap a posi unit in a open diff, why not locate a HEALTHY posi setup in a scrapyard and swap it in? Many people would argue against used rear ends, but it has saved me two AMC's and a Crown Vic. Not exactly high performance, but they were good to 200K miles. Word to the wise, avoid salt covered rear ends, high miles and Excessive rust. If these all apply, and it isnt leaking, it should last a while. Or, maybe I'm just lucky?