Diesel oil has more detergents for cleaning, and because of that can hold more in suspension so it drains with the oil. It also has more ZDDP (extreme pressure additive) for engine protection. The same amount that used to be in car oil when your car was made. Royal Purple, of course, has even more.

If you know the diffs have never been drained and filled, I would do that too. Synthetic GL-5 front and rear, GL-4 for the center, I believe, but look it up for your year.