Hey everyone thank you for viewing this and any feedback/advice will be appreciated. I've got a 2011 G37x with Stillen Gen 3/Ark catback and it is tuned, i recently started it in the morning and waited about 5-10 minutes before driving it, as the gears were shifting i felt something was wrong but didnt pay much mind to it as i was getting late to work. When i got on the highway going around 60 MPH my car stopped accelerating and all that was happening was my RPM was going up and down as if i was in Neutral. I didnt understand what it was at first but i ended up pulling over and started to drive manually, i realized the 5th gear is slipping, as soon as it shifted into 5th it would stop accelerating and RPM would only rise. I dont know what to do about this, i took it to a transmission shop and they said they cant see the problem, they would have to open it up and that would cost 1,000 just to open it up. If anyone of you guys have any clue as to what this could be and route i can take i would really appreciate it. Sorry for the long post and Thanks once again! Ive added the check engine codes i received.

 

AT or MT?
have you changed the fluid in it recently?

 

X models only come in AT setups.
G/L w/ your issue, I'd run those codes by the dealer and see what they have to say.

 

No i havent changed it is 7AT with 75k miles on it , i was a advised not to change the fluid as it might escalate the issue

 

I have a similar issue but it only happens when changing from 4th to 5th , it feels like it's not changing right away the rpm goes up like it was in neutral then it gets into gear it only happens for half a second , should I change the at fluid or is it a bigger problem ,
anyway good luck with your problem ..

 

The "flare" is normal for these transmissions.

 

Please link a source if you're going to make such a statement

 

It's well known that the G37 between the years 09-11 with the 7 A/T flares between gear shifts and has rough downshifts. That is annoying to some (if not many) people, while others like it. Their are TSB's out there that fix it to the best of my knowledge.

Source: https://www.myg37.com/forums/g37-sedan/215807-g37-7speed-transmission-reprogram-52.html

 

Same issue happened to me earlier today. I was driving approx 40-50 mph and out of nowhere the car felt as if it began to slip and down shift. The down shift came with a loud thud, very scary! As I kept driving down the road the trans continued to slip when the rpms exceeds 3k. Driving on residential streets at low RPM has no sign of trans problems... The car is a 2009 g37x with 85k mileage. I am the second owner (I have had it for about a year) and have had no issues.

I have read some similar issues and people have changed their MAFS and problems have been resolved. I am a little unsure where to start. If you have any suggestions from your expierence please let me know!

 

I have a similar problem as I m driving my 09 G37x the gear slips going from 4th to 5th and then it comes down with a thud I was advised to change the fluid but it did not have any effect to it if you guys know the problem please advise

 

hi were you able to solve this problem and how.

 

were you able to resolve this problem,please revert.
ileriadebolu@gmail.com

 

Have you had all the transmission TSBs applied?

 

yes.
as a matter of fact i have changed the tcm on my 7at and i still experience slip at 5th and i noticed theres no DS on the new tcm. Just D and M

 

Sounds like a TCM issue to me.