Dangerous fault

[steveb19]

Hi
We've had my wife's 75 connesour from new ,2003. She loves it and refuses to get something new.
Last fortnight she's really anxious driving it. Three times now she has started braking and the car has accelerated,really shook her up.
My pal plugged her in and got gearbox fault reading.
On another internet site I found some Kia owners had had the same problem.
Not finding anything obvious ,tonight I am dropping the gearbox fluid and changing it as it smells awful and hasn't been ever been touched in 87000 miles.
I'll report back on results.anyone else had this problem?