Hey everyone, I've been having an issue lately with the automatic shifting of my 04 G35 Coupe and I can't seem to figure out what the problem is. I've taken it in to the dealership multiple times and the mechanics are never able to reproduce the problem... it happens sporadically, but enough so that it has me slightly worried.

Around 40 mph or so, or slightly thereafter, my car upshifts, but the upshift is extremely hard and not fluid at all. The car shifts heavily and jolts itself into the gear (which I believe is 4th), and I can feel vibrations through the accelerator pedal from the engine. This usually occurs when I am accelerating gently, and most noticeably when I am driving up an incline, where there is more stress on the engine. With hard/quick acceleration there does not seem to be an issue. There also doesn't seem to be a problem when I'm in the tiptronic mode, so my guess it has something to do with the programming of the automatic transmission. I tried resetting the ECU, but the problem still remains.

I am pretty sure the transmission is shifting up to 4th gear... it's never occured when downshifting, only accelerating lightly in automatic. I recently had a 30,000 mile service completed, and they replaced the auto transmission fluid, so I don't think that is the source of the problem. Otherwise I stay up to date on all oil changes and other service appointments.

Does anyone know what might be the cause of this problem? Any help is appreciated. Thanks!

 

I thought the tranny will shift into 5th gear while u are driving in D to save on gas.

 

Well, I know that at higher speeds 5th gear is where the auto remains... but say I'm accelerating from around 20 mph... once it hits near 40 is when it should technically shift into 4th gear, right? That's where/when the problem has been happening. I could be completely wrong on that point, that has just been what I've assumed. Anyways though, the main issue, no matter what gear it might be shifting into, is that it shifts into it hard.

 

I have the same problem 04 G35X automatic. Mine happens between 3rd and 4th gear at full throttle (right around 6k RPM). It feels like there is a fuel cut-off issue, like its hitting a rev limiter early. All other gears are smooth.

I took it to the dealership and insisted that the head mechanic go on a drive with me so that I could make sure they saw the problem. As soon as he got in the car he told me that he has seen this problem on countless 03 and 04 G35s and that Infiniti essentially rebuilt the transmission for 05 and up. There was nothing physically wrong with the transmission, it is just not the best design (his quote), and that he has seen one car where the shifting was so harsh that the passengers head almost hit the windshield (yeah, that made me feel better!). I had him do a full check (no problems), and reset the ECU (made it worse for the first month). I've thought about taking it to another mechanic to get a non-biased opinion, but it would have been in the dealership's best interest to tell me I needed a tranny rebuild since it is still under warranty.

 

I have an 04 coupe and my tranny shifts fine. Did you try to shift it manually in the trip mode to see if it still shift hard to 4th

 

The trip mode is rough from 3rd to 4th as well, and really harsh when going from 3rd to 2nd unless I'm at a decent throttle. The odd thing about it is that I never noticed any tranny issues for the 9 months I had the car in New York, but I noticed it the first week I moved to Colorado (5000 feet above sea level).

 

This is my first post, and according to the dates Im a little late on the draw,

But wow 1 in 10 people answer the question ever asked in a thread.
Its just the same question over and over and over again with the occasional condescending remark.

Nobody cares about the stats of your particular version of this problem, why write if its not productive? **** ME

 

I just thought the same thing!

 

What is the proper way to shift the automatic transmission in manual mode? Do you lift off the gas? Thanks.

 

No need when shifting up. Shifting down the car does the work for you .

 

People love to be sarcastic and rude on forums because they can hide behind their screens. And others are just natural born a-holes......

 

It would be a lot more fun if the bear knew how to handle a rifle like yours. At least he'd have a chance... Can you eat bear? or is it a trophy?

 

Nice first post!
And the reason you came here is?

 

I have no idea what on earth eating bear has to do with shifting problems for an automatic 2004 G35 coupe but to answer your question yes you can eat bear. you need to make damn sure that you trim all the fat off of the meat though or it tastes really nasty. Properly cleaned though making sure you get all the fat off the meat bear is delicious.