I don't have any experience with the locker but I am assuming that even in 2wd the 2 front tires would be "locked" together but not powered by the engine. If thats the case, wouldn't high speed runs and especially cornering on hard ground cause binding and wheel slip at the front axle as both wheels would have to turn at the same speed. Even if this doesn't cause damage I would think it would affect handling at the very least. I'm sure someone more familiar with the locker will correct me if this is not the case.