If his argument is that a 4wd truck is not 4wd unless it has locked front and rear diffs than there are only two or three available true 4wd trucks on the planet. But it is true that 2wd is really only 1 rear wd and 4wd is really only front and rear two wheel drive by his definition.

In essence his argument has some merrit. If you are in 4lo without lockers and you lose traction to one tire the other tire will not rotate , thus rendering that axle useless. The front wheels will pull the vehicle but if you lose traction or a wheel leaves the ground there as well you will be stuck.

With lockers you will be able to keep traction at all wheels in the event of slippage or a wheel leaving the ground.

But to say that and X isn't a true 4wd truck because it lacks lockers is rediculous. The Mercedes G-Wagen , Hummer H1 (possibly H2) and the Jeep Rubicon (Does the new Tourag have them? I think so.)(I know toyota trucks have an electronic locker available but isn't it only front?) are probably the few domestically available vehicles with factroy installed front and rear lockers.