Towing a s60 AWD

Hey guys, I'm fairly new here. I have a 2002 s60 AWD. I am moving from San Francisco to Texas in a few months with a UHaul, and am planning on towing my s60 to avoid putting more miles on it. The flat bed trailers are more expensive and since they are heavier eat up more gas on the UHaul. Is there a way to unlock the rear axle so I can just hook up the car to a two-wheel dolly? Thanks in advance.

FYI... http://flagstaff.craigslist.org/cto/1701034652.html