I have a 2014 Nissan Xterra automatic transmission with 74,000 miles.  I bought the vehicle new. I had the transmission fluid drained once and refilled at 27K.   

Have I waited to long to change it again? 

I checked the fluid and appears mostly clear with a tint of red.

I'm worried about causing more issues by changing it if I've waited to long.

I have always had problems in the past with transmissions slipping after a fluid change but these were mostly higher mileage used vehicles that I had no idea when it was performed before.

I'd like to keep the Xterra as long as possible but don't want to cause any issues to develop. So I'm a bit nervous.

Thanks in advance,