If you have a manual transmission 350z with replacement version 008 or an '05-'06 Z (which came with this model I beleve) I need your help! My '03 touring had its tranny & clutch assembly replaced under warranty @ 16.5k due to overly loud syncros and supposed hot-spots on the flywheel and clutch cover. Since the repair my new clutch has been exhibiting a horrible buzzing/bearing noise with the clutch ‘loaded’ aka depressed. They did not replace the throw-out bearing at the time of this repair as the dealer felt mine was ‘fine’. The dealer and NAA are holding firm that the noise I am hearing is normal for the new transmission.

The noise appeared first at 4.5k-5.5k when I was shifting and depressed the clutch pedal. Nissan first claimed 'unwound gear backlash' as the culprit and it was a 'normal' noise and refuse to fix the annoyance. I waited a few weeks to see if things would quiet by themselves which they have not. During further tests I then found the noise to also occur with the car at a stand still in neutral by reving the motor and depressing the clutch in the 4.5k-5.5k range. Ah ha! I thought, and took the car to the dealership and asked how can this be gear backlash when the gears are not even engaged? They came back stating again the noise was ‘normal’ and refuse to do anything. One further test has revealed the in the following trials the noise is also present.

Run 1 (3 trials) - Started car with clutch depressed to the floor (in loaded position) where it remained for the test. Shifter was in neutral position and car at a stand still. From idle advanced the engine RPMs to the 5k range and the noise occurred. This is a variation on my previous test where I advanced the RPMs to 5k with the transmission engaged and then depressed the pedal to make the noise occur.

Run 2 (3 trials) - Started car and released clutch to unloaded/natural natural position. Shifter was in neutral position and car at a stand still. From idle advanced the engine RPMs to the 5k range. The noise did not occur.
It is very curious that in Run 2 the transmission would have more components in motion yet the noise does not occur. In Run 1 the throw-out/release bearing would be engaged against the clutch cover throughout the whole test and the noise does happen.

I don't understand how the problem could be related to something in the transmission if the noise can only be heard when the clutch is loaded and depressed. The noise obviously appears to be following something in the clutch and that tends to limit things to the throw out bearing and sleeve, clutch cover, clutch disc, and flywheel. If this was some kind of 'normal transmission noise' as I am being told why would it not occur in both test scenarios? The noise should be happening in both situations unless indeed there is something up with the clutch.

If you fellow Z car owners could perform the above tests to see if you hear any odd noises coming from your vehicle and drop me a note I’d appreciate it! Please also offer any help or guidance as it is certainly appreciated! As you guys can imagine this is very upsetting and down right embarrassing if the passenger is unaware of the problem. Thanks!