Her er hva gutta på mkiv.co.nz sier om saken
----------------------------------------------------------------------------------
The TT Auto gearbox (A340E) is a very strong auto, but it will break if you are running over 300rwkw. This auto is unique to the 2JZ-GTE engine, despite many other Toyota autos also being labelled as A340E autos. The 300rwkw limit is well below the limit of the Getrag 6 spd gearbox (around 500rwkw), so if you are making serious power, make sure you are using the Getrag box. The W58 5 speed that comes with the non-turbo 2JZ-GE engine can only take around 260rwkw before it will break and the 2JZ-GE auto can only safely handle around 200rwkw.
You can make the TT auto box survive longer if you manually change gears when you race it, as this puts most of the torque loading during gear changes through a stronger part of the auto. Also you can get the solonoids upgraded so that it changes gear faster, as this reduces the loading on the auto during gear changes. This will allow for up to 350 rwkw. For it to survive beyond that, you will need very expensive strengthening of internal parts that is offered by several USA Auto transmission companies. When suitably strengthened (at much cost) the auto gearbox can then handle as much power as the Getrag does.
----------------------------------------------------------------------------------
