we should just keep them at a minimum of 3K, preferably 4 or 5

 

My vote with OP's desciption given, is detonation as already mentioned.
Or piston slap depending on how many miles on engine.

 

I also have the similar problem. From like 1k-1.5k rpm, there is a chattering/grinding noise....sounds like transmission. Also when I am slowing down and don't downshift to 2nd (leave it at 3rd-rpm low) and when accelerate again, it makes that chattering/grinding noise.

I thought it was my throw out bearing and when I took it to the dealership, they said it was my transmission. I was pretty sure it wasn't my transmission, maybe affected my input shaft, but hey might as well get my tranny replaced.
They checked my JWT clutch and they said it was still good, so I got my car back. My g was still making the noise, so I took it in today. They checked it out and they said I needed OEM Clutch + Flywheel. They said that the chattering is from my aftermarket flywheels, and that I needed the dual mass clutch. They said it it can possibiliy damage my transmission, and that the aftermarket JWT clutch can't handle the power of G. LOL.

Anywayz, I was wondering if this was normal (not going to ruin anything else in long run), or should i go back to oem ($2200???!!!). Can it be something else??? I was watching the tech. guys at infiniti, and they seemed not 100% sure, so if anybody is/had going through the same problem and know the answer.....PLZ share the knowledge. THANKS.

 

Haha not with gas prices now a days, i go partial throttle at low rpm any chance i can get! But the G's fall on their face at aroun the 1k(a little above) spot, until about 1.5k they get out of that garggling noise coming from the cat.


And i dont think its detontation, that is a "pinging" noise, not the noise the OP is describing, and detontation mainly occurs at WOT at high RPMs, not to mention i thnk this guy is talking about a basically stock G35.

 

Let me clarify:

It is not a grinding sound and I am 99% certain it is not a transmission issue.

I would agree that the noise comes at relatively low rpms such as when turning a corner and accelerating out of it.

I always use the appropriate octane. It does sound a bit like an engine knock.

My spark plugs are only about 8k old.

I have 95k miles on the car.

I am obviously out of warranty.

Oh, I am completely stock.

 

I hear a diesel type noise but only when shutting the engine off

 

A little "knock" or preignition can sometimes precede the timing being readjusted by the computer ...... just a guess without hearing it though. As long as it is brief in duration I'd guess it is not harmful but I'd sure ask dealer to do a ride along and diagnose.

 

+1 Have friends who refuse to run the 93 here and when I ride with them I hear the detonation... Who knows what kind of long term damage is getting done! We recently took Mikes 05 G to San Antone and I filled it up on the way back but with 93; it was quiet, no detonation, and he said it ran great!
He still is too cheap to continue to buy the premium.

 

I know this thread is a bit old, but I have been noticing this same issue. I don't recall ever having this noise before but seems to have cropped up, or simply more noticable since I had the transmission replaced under warranty.

It seems, whenever I am under 2krpm it makes this noise. It doesn't happen at any other rpm range even if i give it gas and I am in a high gear but "low" rpm as long as it is above 2krpm. So I don't beleive it in engine ping but sounds like it is coming from the transmission. Besides I dont see how it would be engine ping if it is less than 30F outside and the car isn't at full running temps yet (running temp doesn't affect the noise either)

I could be wrong though. Any other people out there with this issue?

 

yeah, lots of people are out there with this noise. It just happens to be a transmission related noise and it's normal per infiniti - all new cars on the lot made the same noise as mine when I was trying to solve this mystery. Since then I have just accepted it as normal without issue.

 

Weird, thanks for the quick reply thought! I've been trying to remember for the life of me if it was there or not before the trans change or not. I don't see how I could not have noticed it if it was there.

Does the oil in the trans or temperature affect it at all?

 

you have the same problem? Do you still hear the noise after you changed the trans oil?

For me, i have the same problem here. Always hear a quick scrapping noise (mettalic noise) when acceleration or running at low rpm. It happens only once every single time to start the engine and run at RMP. After that, the car runs great. But it happens again when i turn on the engine and run. So weird. Haven't found any way to solve

 

I haven't changed the tranny fluid yet. I just got a new transmission put in about a month ago so the fluid is fresh already. I am not sure entirely, but the sound seems to be there for me no matter what if i am at the low speed/rpm even after the car is up to running temps. Granted, I am not sure about after it has been running for much over 45mins (as where I been actively looking into the situation coincidentally haven't had any reason to drive around more) However 45 mins should be enough for it to get to running temps I beleive.

Like I said too, I don't remember if my original trans was the same, as I find it hard how I could not have noticed this at all since it is pretty damn loud and rather embarrassing when next to other cars since it seems like the car is falling apart.

 

oh wow, then i guess your car is having a different problem. As i said i hear the noise only once everytime i start and run the car. But it smooths out after, meaning no noise after that. But your car is making noise like every single time you accelerate. You should want to check the wheels bearings.

 

I dont beleive it is the wheel bearings as it only happens underload/acceleration at the low rpm under 2k. If I am at 2.5rpm or more for example and give it gas it doesn't make the rattle diesel-like noise.

I think I am going to check with the dealer, have this looked into. Very rareily I get a metallic scraping noise upon engaging the clutch at startup from a stop too (sounds almost as if something is off balance). however this hasn't happened for a while. Very strange.

I had the transmission replaced due to synchro wear, along with the clutc/flywheer(that combo at my expense sadly, tranny for free though) and I am having more noises then before the replacements. The shifting is buttery smooth though (granted 2nd is always iffy but much better now)