The specs are M14-1.5
That's an F-106 Fumoto valve. (Confirmed at the
Fumoto site). I still recommend the one with the nipple. I love the nipple. And who doesn't?
I use a 10 quart gas can with a gooseneck spout that fits right over the nipple. The can fits just right under the Sprinter and perfectly holds the 9.5 quarts of oil. The DEF jugs are the same, with a gooseneck pour spout and is 10 quarts. I think the Promaster is 6 or 7 quarts, depending on the engine, so that would work. Chrysler dealers throw out dozens of empty DEF jugs a day, they'll give you as many as you want. I dump my oil at Walmart or Autozone (unscrew the pour spout instead of trying to pour all that oil through the spout, of course).