Trans cooler

Re the "too cold" question, I just rebuilt the Torqueflite tranny in my 1996 Voyager. A few years later, they added a temperature regulator valve to the cooling circuit which limits cooling to keep the fluid sufficiently warm. I have one because using a ~1998 valve body. I think it works by bypassing the cooler, since restricting the flow would starve the tranny. I don't know the exact reason, but think it has more to do with affecting the shift points (as stated), and was for vehicles in sub-zero winters. Otherwise, cooler is generally better for transmissions.