Its a 1994 Ford Explorer Automatic 4x4

If one of the tranny selenoids got stock yes it will kill your battery overnight

umm not likely. if your battery is dying it may be the alternator or spark plugs. if your transmission is broken you need a new one.

If the battery is low and the alternator is not charging properly to generate at least 10+ volts,Yes it is possible.The computor needs at least 10 volts to operate.

Possible but not likely. Here is a test u can do. You will need a volt meter ($10 - $20). Take volt measurement of battery both before u start & after u start ur car. If ur measurements after u start ur car is less than 13 volts then u probably need a new alternator. This assumes u have a descent battery to start with that will hold a charge. If ur battery measurement before u start ur car is less than 12 volts u either have a short in ur electrical system draining ur battery or ur alternator is not charging it or ur battery is old & it has a dying or dead cell. l am also assuming u checked the water level in the battery & it is up to the fill rings inside the cell. That aught to get u started finding the problem.