Electrical system drain

Started with the transmission not shifting properly, ABS lights on and battery light on while driving home. Bought a new battery and a new alternator. All was well I thought. Drove about 4 hours to the lake and back. Went to the store that afternoon and it did all that goofy stuff again. Charged the battery then went to the auto parts store to check the alternator. No warning lights are on but the check say battery too low to diagnose. I went to the store and exchanged the battery. Went back to the parts stores and the meter still says battery too low to diagnose. Battery is full and new. Parts store man ask me if the odometer was staying on after I turned the car off so I checked, Yes the odometer is on all the time. He said it has to do with the shifter or shifter switch. I found info that refers to the BCM but not of the other indicators fit my situation like door locks, dome lights dash lights not working.
So, I really have taken good care of this vehicle and would like to keep using it.
help me please!