Hi everyone,

I'm a new member, somewhat lurker over the years. I have an AT 2007 G35S with all options except the active four-wheel steering, and around 50k miles. Just lately, I've been having an issue with the transmission. When the car is in second gear, just before shifting into third, there is a sligh shudder/jerk. It only happens when the car has warmed up, and only during light to moderate acceleration. It does not occur when the car is still cold or under heavy acceleration.

I've taken it to the dealership three times now. While they are friendly (they keep giving me Q50's as a loaner car, which after driving for over a week, I would never buy one ) they have not been able to find the cause. I've been able to recreate the issue for them each time. The first two times, they told me the transmission fluid was off, so they leveled it. I took it back again yesterday and the tech suggested it's normal and likely I'll have to accept it, but they're still going to take another look. I've driven an identical model and could not recreate the issue. This also just started about two months back so it's not inherent to the car.

I have a warranty that expires in a couple months and would like to get it resolved before then, but I'm hitting a stuck, and we only have one dealership in the state. I've seen some posts here with similar issues, but no resolutions. I'm thinking it's the valve body, but they say no codes come up and are reluctant to do anything.

If anyone has any insight, or has had a similar issue and figured out the culprit, it would be much appreciated!

 

Did you try resetting the ECU? Sorry, I don't have a lot of insight to give. If you had the 7AT, I would ask if you had the software update, but I don't think it applies to the 5AT. On a side note, curious why you would never buy a Q50 after driven a few.

 

I did reset the ECU, and also the 5AT had a software update as well that I had applied last month (sorry forgot to mention that...) to correct a touchy throttle and also the ICC lurching. So the software is current.

The two Q50's I've been given, including the one I'm currently driving, have the funky new steering, which feels very artificial. The dynamic of the car has shifted from what I like about my car to something that feels more like a Camry. Also, both cars had the touchscreens freeze up on me while driving, so I couldn't turn off the stereo, lower the volume, or change the station until I shut off the car and restarted it. More of a nuisance than anything. And I don't care much for the overall styling of the car but I realize that is subjective.

To be fair, it does have a quiet and comfortable drive, and has a lot of tech features and overall luxury feel.

 

Thanks...those were my thoughts too. Just wanted to hear some feedback from someone who had some real time with the car.

 

sounds like its engaging abit to fast.. they have a few sensors that talk to each other between the tcm and ecm on the transmission the have a input shaft sped sensor output shaft sensor and the emc has the flywheel sensor.. this tell the ecm and tcm when engagement must occur.

but that doesn't sound like the problem. this sounds mechanical. is it only in 2nd? if it doesnt do it when its hot it could be simply fluid needs to be changed.
a sport/racing clutch engages much faster and causes much harder shifts at lw to moderate speeds as well but thats every gear..
it could be that the gears are damaged(since its just 2nd its highly likely) clutch is engaging too fast or the oil circulation is poor. among a few other things..
take it to autozone and see what codes is gives you..

 

that's easily bypassed..
its a contact coil(like a starter with a coil) that opens to disconnect the stem from the column.. when the car is on it sucks the rod or what it may be back to disconnect it from the drive terrain.. if you simply wire the relay to normally closed instead of normally open it will never engage. its a fail safe system that way if you loose power it will de-energize and you will have manual steering.. wiring it like suggested will do the oppsite so i suggest completely bypassing it by just never sending it power. IE just disconnect it from the relay. or pull the fuse..

 

Not sure if what you're experiencing could be related to fluid, but a couple of my vehicles (not Infiniti) had sluggish AT performance and after a fluid change performed much better. At 50k miles the AT fluid should still be fine but might be worth looking into.

 

Thanks for the input guys. The transmission fluid was replaced around 4k miles ago (along with brake and differential), so I think that should be fine. In fact that was what they kept saying they needed to level off, apparently they overfilled it the first time. But reducing the level didn't help the symptoms.

I should hopefully hear something today, apparently they think they isolated the problem and want to test some stuff to make sure. I'm hoping it's nothing major.