I just got this 2008 G37s coupe yesterday and it is the 5-speed automatic. My question, is 5th gear considered considered the overdrive or is my car never making it into overdrive? My dash display never reads anything above 5th gear. And it seems like the RPMs are a little high going 70 mph in my opinion. Just under 3k rpm.

 

5th gear is considered as "overdrive" with a gear ratio of 0.839:1. Your RPM's at 70 is normal.

 

I appreciate the information. Just seemed like a bit high on the rpm's to me. Can't imagine the revs it spins at 140mph!

 

If it's at just under 3000 rpm at 70 then it will be just under 6000 rpm at 140...