It took me a few minutes to see the broken UCA as I was focused on the weepage around the rear diff cover.
Living in the rust belt one of the biggest issues we have is the unbelievably thin metal cap over the rear diff rusting out and eventually losing all the rear diff oil. And then if you don't notice it running the rear diff dry......
Ask me how I know this............
I did buy a plate steel replacement cover and have it welded on to eliminate that happening in the future.
Living with the whine in the rear end for now.......
Good luck with the fix.......