Gearbox controller is a crucial component which is responsible for correct operation of many subassemblies in your car. The task of the controller is to properly adjust and deliver oil to the appropriate parts of the gearbox. Incorrect operation of this component may have severe consequences for the whole gearbox. As soon as you notice the first irregularities you should have the controller replaced as soon as possible. A prompt reaction will save you a lot of money that you would otherwise have to spend at a later time.