I recently picked up a rear from a junked f-body with disc brakes on it, to replace the one I have with drums. However, the guts are bad- the big gear parallel to the wheels (ring gear?) is missing half of the teeth. I'm not sure about the other gears because I haven't taken the unit out yet, but the ones I could see looked intact. I don't know how to tell what gear ratio it is(was) or if it's posi or not.

Anyways, I want it to end up a posi rear with 3.42 gearing. Is there a way to go from what I have now (busted gear and all) to that without replacing the whole mess?

And if I have to replace the mess, what exactly am I looking to buy?

Any advice would be greatly appreciated, or even a pointer to a website so I can read up and learn it myself. I know nothing about rear ends, except which parts the tires go on

 

easiest thing to do would be to buy the SLP posi for 100 and find the gears you want. the SLP is 28 spline so make sure of what you have before you buy it. then all you'd have to do is set up the gear set and install the new carrier in your rear end. if the rear you have has missing teeth off the ring gear i wouldn't use any of it, to easy for other parts to be hurt and too easy to find another rear and gears.