I had a leak inside driver side then my gauges STOPPED working most of the time on 2002 Volvo S80

Then one day I parked the car never noticed a problem came back and started the car reverse would work but not D or 3rd unless shifted manually i was told it was most likely the computer due to the leaking in the car I'm not site but I know it's not the transmission because it works as long as I shift manually

Asked by for the 2002 Volvo S80