8.75 drain plug

Obviously you will have to drain it to drill in a drain plug. I installed one in mine before assembly. I used a 3/8 npt plug hex instead of the standard square pipe plug fitting that will stick out and applied sealant when I installed it, this way you can put a jack under the diff without disturbing the plug. One thing to keep in mind if you do this is to set the plug off to the side of the ring gear, not directly under it.