All that info....what you can/cannot do SHOULD be in the owners' manual. I know it's not the American thing to do...but reading it does help. Salesmen are interested in only ONE thing. Sell the car. Most likely there is no real training regarding ANY kind of special stuff...except for what is on the sales floor. Ands they, too could care less about "after the sale".
In my case, my 2011 Ranger 4WD was not towable until I put in their (Ford only = $400) "Transfer Case Neutral Kit". Now I tow that pickup witn no problems.
Ford seemingly has little interest in the 4-down towing thing....as evidenced by the very limited number of vehicles that can do it....however, GM, at least in 2011 has the most in the most price ranges.
Once more...i have to say, if you're going to tow 4-down....BUY A VEHICLE THAT CAN DO IT with little or no modifications. At least in my world, buying a motorhome is not an impluse buy...but something thought about for quite a long time....and y'gotta figure out what is needed to make one happy. A "toad" definately can be part of the equation. So...one must RESEARCH.
And what is this lowering the level of the transmission fluid? That mean you have to add the stuff back after reaching your destination? Add/lower/add/lower....holy smokes!