My G35 infinity service manual says for the premium service to replace the automatic transmission fluid and engine coolant at 30000 miles or 24 months, change engine oil and filter every 3750 miles or 6000km. For schedule 2 maintenance it only mentions engine coolant replacement every 60000 miles, engine oil every 7500 miles and no mention of auto fluid replacement. Schedule 2 is for cars doing mainly highway driving in temperate conditions.