Lately I've been noticing what appears to be a mild transmission slip with my 2007 X sedan. I only notice it around 2000-3000 RPM under light throttle, and only seems to happen when the trans is fully warmed up. With light throttle and shift points between 2k-3k I'm feeling an awkward upshift that feels sort of premature and a bit hesitant/vague.

I'm at 62K miles and had the trans fluid replaced about 5-6k miles ago at an Infiniti dealer. Shift points higher than ~3k on the warm trans don't seem to produce this. I also notice (what I assume to be normal) jerkiness when at low rpm doing engine braking (full auto mode) preparing to come to a stop (think 2 stop signs close together).

Anybody experience this or can shed any light? Could dirty air filters cause this? I need to inspect mine, I think they are in need of replacement. Taking her into the dealer tomorrow to see what they say about it.

 

I've noticed that (at least my) trans doesn't like to have throttle input withdrawn at all before a shift (to induce an upshift). It seems to want you to hold the throttle position until the upshift and then reduce throttle. With other cars I've had you could reduce the throttle to induce an upshift smoothly, but realize every car is a bit different. This normal?

 

I just noticed this a few days ago in my car, 68k on it. I was wondering if it was the right at the point where the torque converter starts to lock up. Same thing though, only notice it at low rpm throttle input

 

I noticed this with mine too. It seems more common when stopping at a red light and right before the car comes to a complete the light turns green and I'm starting to accelerate i can feel the car rev up and it's stuck between gears.

 

Had an Infiniti tech ride with me today, he thinks its the torque converter "locking up". From what he was saying seems like this lock up is normal to some degree. They will be reflashing to see if that improves things. According to their records my car has not had any reflashes done, but I'm not sure that is correct.

I'll know more this weekend.

 

I'd be careful with their reflashes though. Folks who didn't care for the harsh shifts got reflashes done that calmed it down too much, and then wished they hadn't done it in the long run, because apparently, there's no going back to the old original one.

 

VQsmile: Do you know anything about the Torque Converter lock-up? My shifts aren't bad aside from the condition I described above. It's like a little hiccup or slight bump after shifting into 3rd or 4th at low speed and light throttle.

I'm wondering how/if a reflash could change the TC operation...

Also, were the reflashes for "harsh shifts" as you mentioned, or for the throttle tip-in/sensitivity? I'm fine with the throttle sensitivity, I like the responsiveness off the line.

 

No, not terribly much; mostly what I've read here and there (I've got a 6MT).

If I'm not mistaken, the transmission control logic can control the lock/unlock process, so yeah, it would seem that a reflash of the logic could make a difference.

I think I've seen where they did reflashes for both throttle or shift issues, but I think the result either way is that you do lose that crisp, responsive throttle sensitivity.

But again, this is pretty much all from memory, so you may want to verify for yourself just in case I'm FOS.

 

Update: Dealer performed at least one, possibly two transmission reflashes. Result: Still experiencing the "transfer case lockup" although not *quite as noticable. It did however smooth out shifting in general, and the car feels much more "tame" than before. It is much smoother in stop and go-type traffic, and the trans doesn't seem to get as confused as much. It definitely took away some responsiveness...honestly feels more like a G37 now, with the more gradual/tame acceleration feel/torque curve. My butt dyno is trying to tell me that the car feels a tad bit slower, and more throttle input is needed to get a comparable level of acceleration.

All in all the car/trans seems to operate more intelligently, but with slightly less sporty feeling.

 

Hey guys,

I have noticed this same issue in my 2007 G35 Journey.

Sounds pretty common.

Previous owner installed a power pup and any map I use on there has no effect on the 3rd gear blip.

Usually happens around 3K RPM under light shifting conditions. It's like it shifts into 3rd, then kinda blips up 100rpm, then back down.

Annoying, but not crazy.

Im wondering, does anyone know, let's say I take it to the dealership and they flash it and I dont like it, would the power pup chip allow me to keep the flash they set but add the Premium setting from the chip?

Let me know!

_Michael

 

Have an 07 g35S with 98k on the clock and have just in the past two wks noticed this bumping usually 3rd gear just as described. Feels like a failing torque coverter to be honest or a problem with TC lockup logic in the pcm. TC is stalling too high at higher rpms, not stalling out literally but as if torque isn't being multiplied as it should be. Dunno. Just bought it 2 months ago and have been beating on it good. Gonna do plugs and tranny fluid and see what if any reflashes are there. Feels like timing advance has been cut back since I don't feel that runaway feeling of power increase from timing advance and extra fuel and a perfectly orchestrated valve train. Dunno but its discouraging as hell. Feels like a G25 and not a g35. It was a real serious screamer for 7wks... now its like an unlubricated sled ride.

 

I had a similar problem with my tranny. Took it into the dealer and they said I had a bad valve body. They replaced it under warranty and it's been running prefectly ever since. The service advisor also had the same exact problem with his G37 coupe and said that it is fairly common for the valve bodies to have flashing on the internal casting which causes the flow paths to clog up over time. He said they replace at least a couple of these a month under warranty.

 

What year u have? Do u have the update flashed to your pcm for the tranny by the dealer for the tsb or recall?

 

Are you refering to the ITB12-027c TSB? If so, I think this is only relative to the 7 AT's, and not the 5 AT's. Do you know if they have a different TSB for the 5 AT's?

 

I have reason to believe your problem is different. The fact that when my AWD fuse is pulled the issue goes away leads me to believe the transfer case is the culprit. my symptoms are EXACTLY as he describes. I have left my fuse pulled and am running in RWD until this issue is resolved; if they sell the appropriate parts to fix it. If not, 6MT here we go. Do you have AWD? (On my iphone sorry)
I read somewhere that the issue is caused from the "electronically controlled coupler" in the T case assembly. Pulling the fuse cuts power to this coupler and will render the car RWD but there will be no shuddering under hard acceleration, low speed tight cornering, or part throttle low gear take offs. Someone with hands on experience with the AWD system chime in.