Do I need to change the oil in an automatic gearbox? If so, how often?
There are essentially no service routines recommended for automatic transmissions.
Most car manufacturers claim that the transmission is "sealed for life". However, like any oil, transmission fluid quality deteriorates with use.
For the transmission to remain healthy, it would be wise to have the fluid replaced every 25,000 to 30,000km. The fluid replacement job requires some special equipment, which usually only transmission specialists or authorised workshops would have.