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

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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