I have a 2015 GMC Sierra 4wd with 244,000 miles. Over the years I’ve had the service 4wd message. I’d dismiss it and all is fine. Last night it came back I dismissed it and tried selecting 2wd or 4wd and it won’t do anything. I suspect a low battery because everything was acting different with the transmission. Wouldn’t go in gear forward or reverse, after several attempts it went in drive. After charging overnight everything seemed fine except transfer case wouldn’t move out of Auto position. Anyone else notice these batteries only last about 3 years?