Greetings from Colorado. New member here. I come to this Buick forum, because I am striking out in locating the information I am looking for anywhere else. Though I do NOT have a Buick, I do have a 67 Firebird and my question regards the 8.2 posi unit, which I believe is the same or very similar in the Buick as in the Pontiac. I have found a few 8.2 posts on your forum, and it seems that the knowledge resides with some of the members here. Some background, my car is a 67 Firebird with a factory Pontiac 400. Transmission is a TH400. I am in the process of changing to a Muncie 4 speed, and with that, I need to change my rear end gearing as well. I have a new set of gears in 3.73 as well as 3.90 to put into the rear end. Also just acquired a 67 Pontiac Firebird posi unit to replace the current open rear in my replacement diff housing. I would like to open up the posi unit to inspect the internals before I go through the trouble of installing it, only to find out that perhaps, it is not usable or that it is in poor shape. I cannot locate anywhere online, a good reference, perhaps with pictures, as to how to go about opening up this unit, what to inspect, how the parts inside should look like if in good usable condition etc etc. I don't want to just start taking the bolts off the unit, only to discover there should have been some kind of specific process to follow, or to have it blast apart on me when the last bolt is removed, and find myself without a reference to re-assemble it afterwards. I have seen one post that did talk about machining some surfaces, but not highly descriptive. I am a gunsmith by trade, do have both a mill and lathe in my garage, but some better descriptive guidance as to what to look for, what to machine etc, would go a long way in ensuring I don't F this up. I can, if need be, take pictures of the unit if that will help at all. Hoping someone here can guide me or throw me a lifeline. Thank you all very much for even taking the time to entertain my non-Buick post.