I haven't driven a Hummer before, but from the military guys I've been talking to says there is some type of a traction control system activated by the brakes (assuming this is the Humvee, military version). Is anyone familiar with this, and is this on the Hummer too? I was curious because I haven't heard of this type of system on any other offroad vehicles (Land Rover, Toyota, Jeep). There is also 3 different transfer settings 4WD, 4WD high lock, and 4 low. Anyone know the differences between the three? I know the 4WD setting would be the standard driving setting, but the other two? If it's anything like a normal 4x4 with a transfer case it just lowers the gear ratios. But I heard there was one setting that would lock the differentials and allow all four wheels to turn at the same speed.