Just bought a 2016 X5, 4.4ltr twin turbo. Everything was good on the test drive and when I picked the car up. I stopped to refuel as it was on 1/4, after filling the gauge only read 3/ ish. I got home and came back out a little later had a bit of trouble starting the car, after a couple of tries it started and the fuel gauge is now just pointing down. The range appears to be going down as expected. I also on a 70km drive on highway had 'transmission temp too high' warning and the car said drive moderately, reduced power. I stopped for 5 mins and that went away. When I had issues starting the car I put a battery maintainer on, after 20 mins it showed full, battery voltage 12.6 then when running 13.9, so I know alternator is good. Could this be a bad battery causing these faults. I am inclined to get the transmission serviced just in case. Any advise would be appreciated.