I'm not convinced with size of fan you are talking about that air would be forced down around the transmission, especially when the vehicle is moving. Air movement under the vehicle will act like a blanket as in the 4 wheel Morgans. As you say the air that will be drawn in is nicely heated by the engine which seems counterproductive.
Bruce 1964 4/4 Series V Comp (Megan) 1994 +8 (Maurice) tis no more 2013 M3W (Olga)
