Greg, I doubt the hitch or its capacity depends on the drivetrain of the vehicle. I suspect that exactly same part is being listed as having a capacity determined by the vehicle, so when you change vehicle specs, you see a different capacity.
My built-by-Reese sold-by-Toyota hitch has no capacity listed on the hitch; it refers only to the owner's manual, which is currently standard Toyota practice. In other words, it is designed to capable of at least what the van can handle. In some ways this is preferable to listing something like 5000 pounds (the Class 3 limit) on a hitch which can structurally handle that, and having people think that makes their Baja capable of towing 5000 lb!
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
STATUS: No longer active in forum.