So I have a G37x 09 and it slips from 4th going into 5th it’s a 7speed AT. It revs up like in neutral and catches the gear and once the rpms come down you feel the car jerk but no lights on the dash or anything. Any suggestions what it could possibly be?

 

There is no definitive answer, only ameliorative suggestions.

1. Try changing trans fluid. Infiniti claims unlimited life but that can't really be the case; others have reported improved shifting after a fluid change.
2. Could be slightly clogged valve body passage(s) due to that old fluid.
3. Could be the a clutch pack beginning to go.
4. Could be the trans computer beginning to go but unlikely.
5. ?

Others may offer more or better suggestions.