I may be full of baloney, I don't claim to be an expert, but I've never heard of an AWD vehicle that could be towed 4 down, although I have a Jeep that has a transfer case that allows you to shift between 2 WD, 4-Hi, 4-Lo, and AWD that can be towed 4 down by putting the transfer case in neutral and the transmission in Park. If I'm not mistaken, the Highlander does not have a transfer case with a neutral position, nor does it offer old-style 4WD, which is what makes the Jeep work. All the "straight AWD" vehicles I know about, bad things happen if you attempt to tow 4 down. Just sayin', and if you find out otherwise, I'd like to know.
