Horrible rattling/vibration noise in 3rd gear in higher RPMS

tibor370

Hi guys,

This is my first thread/post on this forum and unfortunately it's regarding an issue that just popped up on my manual 370z.

During a spirited drive today (nothing too crazy though), my car started making a nasty buzzing/rattling noise that seems to be coming from the transmission. The noise is accompanied by a strong vibration in the shifter knob (stronger than usual).

The strange thing is that the noise and vibration only appears in 3rd gear between 4500 - 6000 RPM. It's not there at all below 4500 RPM and it goes away completely above 6000 RPM.

I think it might be also affecting gear 4 and 5 (in the same rpm range), but to a much lesser degree (I can barely hear it and feel it). I didn't notice it in gear 1 or 2.

The car drives completely normal besides the noise.

Here is what it sounds like. It's especially bad when I rev up to 6000 RPM and then let the RPMs drop (last 10 seconds of the audio clip).

Any ideas?

tibor370

Not a single reply?

I just got back from the shop and was told that the transmission mount is the most likely culprit, resulting in the strong vibration in the shifter and the noise which accompanies it.

So I was told that the transmission mount should be replaced.

My car has only done 22,000 miles but it's almost 10 years old. So maybe the rubber mount deteriorated over time?

Any thoughts or experiences?

Spooler

It sounds like the shifter knob vibration. Do a search on here. There is a fix for that.

NVSTR

I have the same issue! Havent been able to trace it down.

s2krazyyy

I had this issue where vibration was present at high rpms. Try pulling off your shift knob/boot and pull up the rubber part under it. I pulled mine up and ziptied it so it wont sag down, it got rid of my vibration.

babyzilla

So...I had a similar issue and was never able to pin point the problem. It occurred at high RPMs in all gears for me. Although it didn't sound good at all, the car seemed completely fine, so I never bothered with it (just thought it was another quirky issue with the Z). Then I had the dreaded CSC failure and replaced the clutch and master/slave cylinder. The noise has completely gone away and drives better than the day I bought it.

I think we can agree it is a transmission issue. I have a feeling if you make the same changes I did, your issue will go away. I'm just not sure if it's the CSC or clutch.

SouthArk370Z

Very possible, especially if the car gets driven hard (sounds like you don't baby it). They tend to get hard over time and can shrink a bit - the looser fit plus the harder "rubber" can lead to Noise, Vibration, and Harshness (NVH). Could also be caused by one of the other drivetrain mounts (eg, the differential bushing which has a tendency to rupture).

I'm too lazy to look that up but Spooler seems to know his stuff, so I'd look into it if it were my car.

Worth looking into.

Another possibility to look at. 370Zs are infamous for CSC failures and other clutch issues.


I'd first look into what Spooler and s2krazyyy suggested; mounts, bushings, and clutch parts are pretty expensive and not that easy to fix even if you have a well-equipped shop.

Edit: First thing I'd do is change the transmission fluid. There are several threads about which brands, weights, etc to use. Might as well change the diff fluid while you're at it. Probably won't cure the vibration problem (still a very small chance it will), but needs to be done if you still have factory fluids.

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brainrain

Hello @tibor370z

I think I have the same issue, I listen your audio file, I have same rattle noise especially at high rpm on 3rd gear and then let the RPMs drop.

Did you find any solution for this ?