Originally Posted by Quicksilvers

Yes, if you neglected to change your transmission fluid on time definitely change your transmission fluid first and diagnose from their. If you can’t change your own transmission fluid on your own have a reputable shop you trust change your transmission fluid for you or take your Z to a Nissan dealership service department and have them change your transmission fluid for you.Overall the 7AT transmission is a solid and reliable/dependable transmission unless it was damaged previously? Was your transmission firmness ever adjusted by your Admin tune? You can try going back to your stock tune temporarily to see if your transmission shift points or firmness changes. Once your transmission computer module calculates load the shift into the next gear will be almost instant except overdrive. Definitely let the transmission shift itself do not use manual mode until this issue has been diagnosed and repaired. Worst case scenario depending on what is found when diagnosed transmission rebuild/replacement or transmission computer module replacement. I hope you have warranty left to use.