guys, need explenation for whats showing below, and you can even try it, then let me know what you got.

manual mode on 3rd gear speeding from 1500 rpm till redline @7500 rpm (HR A/T)

it also happened to a friend of mine, he has 08 G35 Sedan

http://www.youtube.com/watch?v=fshaP5p_TTc thanks

 

I see nothing wrong..

 

Let me point it for u guys.

Watch the rpm needle @3750rpm

 

Just a thought, but maybe you should let the car warm up first? Romping on a car that was just started up can cause all sorts of problems. Cars are meant to be driven at operating temperature, which would be that window displayed on your coolant temp gauge that you are not in. Not to mention the ridiculously high oil pressures that occur at pre-operating temperatures.

Second thought is: pick a correct gear. It is clear that you could have pulled that through second gear, and possibly first at the very beginning. Just because it downshifts into 3rd at around 15 doesn't mean you shouldn't downshift it into 2nd before you floor it.

Third thought: may be a cam changeover or something timing related that is changing.

Fourth thought: my car did the same thing when I was running a true dual exhaust and no tune. Once I got tuned it cleared up immediately. Any mods?

In the end though, it pulls strong and shouldn't hesitate at that spot using the correct gear choice, so I'm certainly with rt on this one: I see nothing wrong... Driver error if anything

 

I usually don't drive the car before the operating temp reaches 85 F.
The gauge shows that car was cold Coz we are in winter. That time when I recorded this video, I was driving in a highway for about 45 minutes.

Plus, the same thing happened to a friends car which has the same exact engine

 

Then you have bigger problems, the temperature gauge should be a little below half no matter what the outside temperature is, might be time for a new thermostat.

 

I stay an the Arabic gulf region (Dubai), and I've using the car for 2 years and half. The normal temp that the needle covers the line above the C (cold) line

 

If the AT is in manual mode, the transmission should still downshift when needed to prevent lugging the engine. When that happens, it'll stay in the lower gear until you shift it up.

I see the little hesitation in the acceleration at 3750. Maybe that's when the valve timing is changed.

How fast was the car going when the accelerator was floored? How fast was the car going when the video ended?

 

No it won't, if you're doing 9 MPH in 3rd gear and floor it, it WILL stay in 3rd until the ~110MPH 3rd gear redline. You can't "lug" an auto tranny Z per se, considering the stall speed is greater than any lugging range one would be in.

 

Really? In the mid-Missouri winter mornings when I'm going to work at 4am and it's -15, the car is usually warm in 5 minutes, idling or driving easily at low rpms. Could be a bigger issue with your computer.

 

When I started flooring it was around 25 mph. The was doing 115 mph at redline.

Gulf specs Z's comes like this, the highest temp in normal cruising is 185F, and it might go up to 194F when I keep pushing it.
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Anyways, I think this is the closest explanation to what happened. Keep in mind that the Z below has a DE engine.

 

I reread the owner's manual, and it says

"In the manual shift mode, the transmission automatically shifts down to 1st gear before the vehicle comes to a stop. When accelerating again, it is necessary to shift up to the desired range."

I interpreted that to mean it would downshift to a lower gear when necessary, and stay there until you shifted up. I haven't played with it that much, so you're probably right about how it works.



Could the hesitation in the engine acceleration at 3750 rpms be the torque converter locking up?

 

Yeah he's right.

 

Thats exactly what it is.

 

Bringin old thread back to life, but I have g35x vq35hr sedan and the same problem (63K miles).

I ordered Lubegard's Instant Shudder Fix, hope it would help. Has anyone solved this problem (maybe by changing the torque converter?).

 

What problem? The little hesitation at 3750 is the torque converter locking up, and that's what it's supposed to do.

I just noticed the OP in the video is running his engine to redline when it's not even close to being warmed up. That's not such a good idea.

 

Lol give me a call when you need a new again op shouldn't take long at all!

 

that's the normal running temp in Gulf spec Zs.

 

The problem is that this hesitation came only couple thousand miles ago (i'm at 63K miles now), so it's not really normal.

Hope Lubegard's Instant Shudder Fix would help, but maybe someone has another solution...

 

I wouldn't put anything in the AT that's not recommended by Nissan. They know what's compatible with the internal parts, and they have a vested interested in making sure it'll work together for a long time (read: until the warranty is done).

The additive guys are only interested in what works to get you to buy their stuff.

Your hesitation would have to MUCH more noticeable than the OP's to make me want to do anything at all to the car.