Just to add a little bit to the 2 tire spin with an open diff question. If traction is equal, "most likely" (key words!) both tires will have the torque applied (or split) in equal amounts. You may not get this off the line all the time, being that as soon as one tire loses traction, it takes all the torque....just like water, follows the easiest path. Anyway, if one gets into some loose stuff, that one will start taking all the torque (even if both had been spining) because it's easier to spin (still a split, just not 50/50, more like 100/0) and result in just one spinning. Any slick conditions and usually a sideways movement will get both spinning also for basically the same reason, traction or grip is basically egual on both sides. And please do keep in mind that as long as both are spinning and the surface stays somewhat consistant, they will both spin until you gain grip with one or both tires or you "toast" one. Sorry, just had to throw that last bit in! Hope this helps you with the understanding of your open diff, a little bit anyway!
Thanks to everyone for all the great info here-it's been a very big help to me!!
