After doing some research, I have learned that the g37 automatic transmission suffers from transmission flare. I currently own a 2009 g37x sedan with 125k miles. Latley I have noticed that more often the rpms jump by a few hundred before changing gears. I have had thr csr for 3 years and have noticed this happened every once in a while. I am not sure what gear it is, but,I think it is 4 or 5. It does not happen with every gear or every time I drive, I only notice it when I will be accelaerating at around 2800k rpms and as the car is about to shift (after 3 years I have the shifting memorized lol) I will take my foot off the gas a little as I am done accelerating. Somtimes right as the car is shifting the rpms jump. It seems like the transmissions lagging when this happens as it is not as smooth as a regular shift. I have read online about the flare and am hoping it is that but I am worried that the transmission is actually slipping. Throtle response is normal and there is no lag on acceleration, just seems like the transmissions lags a bit before shifting and the rpms jump a bit. I had the transmissions fluid changed at 108k as well. Through my research it seems like it may be the flare and the torque converter. Any input would be great, thanks!

 

It is normal as far as I can tell. Should be 4th gear.