Hi all. My wifes explorer has been exhibiting the problems with 4x4 that most people have with the shift control module. When reading varoius posts I have seen some say that issues with voltage may be part of or a contributing cause of this. We have just over 94K miles on the original battery and expect that it is getting weak as we have had some slow starting when it is very cold. I put a charger on it a few times over the last two days and it charges and finishes and charges and finishes so I am pretty sure I need to replace the battery without ever testing it or even reading the voltage. My questions: 1. To avoid the problems with the replacing the battery on a high mileage vehicle with the check eng. light, etc., can you put another battery in parallel connected to the battery leads so that you never lose power to the computer? 2. If not, is there a reset procedure? I have seen some posts that say something about leaving one lead disconnected and turning the key on. 3. On another note, I looked at the VIN sticker on the door but was unable to figure out the manufacture date just in case it is the shift control module. How do I tell when it was built and what generation would that make it? Thanks.