Myself, I did a drain an d fill X2. Use only Nissan trans fluid IMO. My 03 Altima SE 3.5 auto uses D type fluid. Only fill what you drain unless your trans is leaking. I drove for about 500km, then drained and refill again. Both times I got out 9 litres of fluid. I did not change the transmission screen( there's no filter). I've read in other forums that flush and fills may cause issues with transmissions. hope this helps.