Possible engine issue,need help to diagnose

pat_0701

Hey guys,
I drive a 2010 G37s coupe 6mt, 64k miles on the odo.
Since I got my car fixed from an accident, it has been behaving weirdly.

Basically, whether I'm in 1st or 2nd gear and I'm accelerating quickly there is this unpleasant sound that erupts.(between 3.5-4.5k rpms) This does not happen in any other gear.
Sounds as if it is coming from my engine or maybe even my transmission. The sounds can be almost described as a finger rubbing on glass,
although much louder. This sound also happens when I am driving through rough roads in 1st or 2nd gear with a heavy foot.

I've been trying to pin point this noise but I have no luck. I've been searching forums everywhere, everyday. It's getting pretty frustrating. Any help or input would be highly appreciated. Thanks in advance!

https://youtu.be/_T7mC3i5xn8
P.S. I apologize if you cannot hear the sound well from my video, as I realized my phone did not pick up the sound loud enough.

pat_0701

bump, anyone?

Chuck33079

What happened to the car in the accident? What was damaged, and what was replaced?

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pat_0701

It was a drivers side front collision. The frame was a little bit bent but it was taken care of. The items replaced were : front bumper and assembly, headlights, fender, AC lines, and the intake airbox.

I've been getting told it might be my motor mounts but I do not notice the car drifting away when I accelerate and do not have my hands on the wheel.

Chuck33079

If it didn't occur until after the repair from the accident, why not give the car back to the shop and tell them they missed something? Take them for a ride along and point out the noise.

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pat_0701

Good suggestion, I did just that. I took the mechanic out on a spin and he looked under my car on a lift. He could not diagnose what was wrong. I'm hoping someone had this problem before that is why I took it to the forums. If all else fails, I'll take it to an Nissan/Infiniti dealer. I should clarify:the car behaved fine for the first week I got it back. But then it started to be strange. No power loss or anything, might be my suspension or hopefully my shift forks.

SouthArk370Z

First thing that comes to my mind is a bad drivetrain mount. I'd start at the engine and work back to the differential.

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pat_0701

Thanks for the reply. The drive train was the first thing checked out by the mechanic. He said nothing was loose under there.

Going back at what I said, this only happens 1st and 2nd gear. I tested 3rd and 4th gear under the same scenarios where the sound would erupt if I was in 1st or 2nd. No sound or anything, it was perfectly normal.

Rusty

What gear was the Z in when it got hit?

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pat_0701

I think it may have been 2nd or 3rd gear, I can't remember exactly but for sure one of those 2.

Rusty

Sounds like maybe a tranny problem. During impacts, sometimes the tranny gets it too.

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pat_0701

Thanks for the input! I'm going to have the tranny inspected when the time comes to replace my clutch and flywheel. Hoping I don't have to replace the whole trans...

Chuck33079

You might need to get it inspected now, before it potentially eats itself. Waiting might not be the best idea.

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pat_0701

If I go light on the pedal in 1st or 2nd gear it does not make the noise. The noise happens on WOT. But you're right, it may be safer to get it inspected soon.

Chuck33079

Well, whatever is causing the noise may very well be happening at light throttle, just not in an audible amount. If it were my car, I'd park the thing until I got a clean bill of health.

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