Rear mean seal (had to do it twice, had a 8 bolt seal, they are similar, but the 8 bolts is thicker .
Also good news, the oil on the top was from an untighten valve cover (cover was new from the previous owner) ! from all the bolt 6 of them were loose, I can remove them by hand !!
carbon need to be done. Go the poor way : soak in brake cleaner, brass brush and ending with a sand blaster gun with soda in it.
Catch can and water/meth on the way to keep this cleaner.
Also painted and change the rear subframe and diff bushing
