Maybe the trans guys here can answer my question. I was wondering if all automatic transmissions do the same thing go foward, reverse etc. Why is it that they use different trans fluids. Also why is it that if you use something other than the fluid specified as in another transmission fluid there could be major damage. Aren't these trans built the same way with the same components and materials or can someone please tell me what is different with each automatic trans. I just keep wondering what is the differences internally between a 6 speed auto chrysler, ford, gm and foreign transmissions.