Loud Clunking Noise

When you say the noise is more pronounced on cornering I would suggest you take a look at the spider gears in the differential. When moving straight ahead the whole diff carrier is turning as one unit, but on cornering, because the inner wheel has a smaller effective turning radius as the outside wheel, the differential has to compensate this difference.
This is where the spider gears come into the game.
It sounds like you're gonna have to pull the 3rd member & take a peek inside.