[grill-n-go]

The way the dealer explained it to me is that with the V6 they DON'T want you using a WDH, and they characterize it as a "weight carrying" receiver. I think they do this because it's offered with a 2" receiver which is typical of a class III hitch while the V6 4Runner is only rated for 5000 Lbs. While the V8 is designed to meets all the requirements of a class III hitch (7,500 Lbs) and can be used with a WDH.

The aforementioned is my opinion, peppered with opinions from a Toyota dealer and presented in such a way as to seem factual when in fact it's only swag