Yes, it would be a good idea to do a drain and fill. If it's never been done, the fluid is probably quite dirty by now. It's always a good idea to do a drain-fill every 80,000 mi. However if someone recommends to do a flush, don't do it. It could very easily damage the AT.I have a 2006 altima, 2.5l with 154,000 miles. Is it safe to change trans fluid, I don't know if it's ever been done.