So a few hours and a few hundred miles after buying my van, heard a LOUD THUMP THUMP THUMP THUMP on the highway. Pulled off. Wheels looked fine, some play in the CV so I towed it home from there.
After inspection, there's A LOT of play on the passenger side CV where it meets the front diff, and play matches the sound, so I'm thinking the needle bearing in the front diff blew out. This seems to be a very common failure point for AWD.
Front end rebuild is in order. While I'm pulling everything out, is there either a heavy duty rebuild kit or a front diff swap that improves reliability?