70,000-80,000 miles or 125.000-150,000 km. If it has no dip stick the manufacture says that it will never need to be changed. But honestly I dont believe that.
how much trans fluid do i add when changing trans fliud in my 2000 focus
every 50,000 miles if it is an automatic trans.
It is called "lifetime trans fluid". That is true, if you never change it your trans will die and thus it did last the trans lifetime. Have it changed by a pro with correct ZF trans fluid, it will cost about $30.00 per qt. but you will ruin the trany if you use any other kind.
What type of trans oil does and how many lts
All you can do in your driveway is drop the trans pan, replace the trans filter, replace the trans pan gasket, install pan (no gasket sealer needed or required!) and refill what fluid drained out in the process which is aprox half of the fluid the trans holds. Take it to a trans shop if you want a complete fluid change. They will have the equipment to do a trans flush.
how do you change the trans fluid on a 1997 328i automatic trans
There will be a fill plug on the side of the trans, fill it until fluid comes out of the hole and seal it back up.
On any vehicle, the filter and trans fluid should be done at least every 50,000 miles. I actually change ALL my trans fluid every 30,000.
remove the trans pan and change the trans filter at the same time
You do not change the trans fluid. It is a life time synthetic fluid.
You should change all trans fluid on any vehicle at least every 50,000 miles. Even less in some cases. Refer to your owners manual.
they are a sealed gearbox.