As has been said, Jeeps during WWII have generally had a bridge classification of "2" but of course like all things military, you'll also see them with a "3", as well jeeps towing a trailer would have a "3/2" bridge sign, and as Jordan pointed out, some jeeps even had a "5" (esp. some AB-modified jeeps). Why they classified as a "5" I haven't a clue why, as I doubt you could get a jeep to weigh that much and still move
Hope that helps,
Tim