Posi Unit Gears

[ShortBedChevy]

Well, i know what i did... I removed the 10 bolt cover, and took a peek inside the rear end early this morning... I broke two gears that go on the inside of the posi unit.. They are the ones that go on the sides, not the top/bottom i believe.. How can i replace these? I also need to replace the bar that they sit on as well, because it has a massive groove in it.. do i need to buy a whole new posi unit? if so i could probably get one from the junk yard cheep right? and install it fairly easy? the ring and pinion appear to be in fine condition, no real pitting or no broken gears or anything... How easy is it to replace the posi unit.. and does anyone have any websites/pics/info on how to do this?
Thanks a bunch!!!!!!