The 71st Armored Field Artillery had (3) M4 tanks used for forward observation. They were  M4 Sherman -Mid Production tanks, cast front - welded sides, with a Continental R975 C1; 9 cylinder, 4 cycle, radial gasoline engine and a 75mm cannon. More pictures and a better description of these tanks will follow. Below are some good links for more on the M4.

  M4 Sherman Tank - The main American tank in World War 2    http://www.2worldwar2.com/sherman.htm  

  M4 - Overrated and Underrated Tank    http://anonymous-generaltopics.blogspot.com/2008/05/m4-sherman.html

  Medium Tank, M4 / M4 (Sherman)     http://www.militaryfactory.com/armor/detail.asp?armor_id=40 

  M4 Sherman Tank      http://www.strijdbewijs.nl/tanks/sherman/eng.htm

  American Fighting Vehicle Database    http://afvdb.50megs.com/usa/m4sherman.html

   M4    Wikipedia     http://en.wikipedia.org/wiki/M4_Sherman