I have a 2009 Infiniti G37s that I bought at 90,000 miles. I now have 180,00 miles on it, and I haven't changed the transmission fluid in that time. I'm not sure if it's ever been done. It still shifts really well. Should I replace the fluid, or is it a lost cause?
Clarification: How does the fluid look? Any burnt smell to it?
If fluid is clear you can do a filter fluid change, no flush. If its cloudy or dirty, sell it or drive it til it dies.