allmightsu

Hello guys,

(++ video link - )


Until today I was only reading here, but the time for my first post has come (bad reason).

I have a 350z HR, year 2008. It has 19k miles on it. I bought it like.. 4500 miles ago. For me, it feels like a brand new car..

Recently I bought a JWT single mass fw & clutch combo as well as JWT HD CSC and Tilton master. So far so good. I installed all the parts, I was aware of the chatter, which is not that bad at all, I did the break-in procedure, honestly I couldn't feel any improvement with the acceleration, but at least the clutch engagement is now, I believe, improved.

So.. the break in process was fine, afterwards I've started to push the car hard without any issues (just the chatter) and yesterday I went to some place to do few 1/4 miles starts (no drag tree and time counter). I did few starts, become disapointed again how slow she is (come on, no one likes his car no matter how fast she is) and when I left the place I heard a whining noise. Ok.. some puley of the driving belt I said.. but few miles ahead I managed to see that it is coming from the "after engine".

1) When I engage the clutch it stop;
2) It depends by the revs;
3) It doesn't matter is the car moving or not;
4) It doesn't matter is a gear engaged or not;
5) It only matters if the clutch is released or not;

So.. the whine is like a diff bearing or like a supercharger. When I press the clutch, so the friction plate and the prime shaft of the tranny stop spin, the noise disappear. The diff is not a suspect as she makes the noise while not moving as well. The engine also is not a suspect. The secondary tranny shaft or the driveshaft neither.

The question is.. I know the chatter, but how likely is the tranny to start whine because of the singlemass fw? Is this being part of the so called chatter? How often do the HD CSC fail? I mean.. the bearing should spins all the time, but maybe when not engaged so the load on it isn't that big, it whine and once it is engaged, the load makes it not whining. Like a broken bearing on AC compressor. When AC is not started it whine, once it is engaged it stop, because of the load on the bearing.
So yeah.. how often such slave cylinders fail?

When accelerating the car, it whine more compared to decelerating (on the same revs). So what is being loaded more on accel than decel?

​​​​​​The suspects are:
1) bronze pivot bushing (it is the same. I ordered Nismo needle, but I decided to not put it, so I left the old bronze one). But I doubt pivot could whine that way;
2) the new CSC. Yep it could be;
3) some bearing on tranny prime shaft is gone after yesterday;
4) noise is normal for single mass fw. I also doubt that, as the first 200 miles city driving it was not there. Plus like 200 miles normal + hard driving. It went after the few starts I did yesterday.
​​​
I am doing my car by myself, so no money would be spent for labor, also have all the old parts, so I can fully revert and test. The only problem is the time. I know that before I remove the tranny I cannot really know the reason, but yeah.. just wanted to collect some opinions.

EDIT: hold on. While I was re-reading the post I started believe, it is not a CSC. When I press the clutch I can literally hear the noise stopping rev by rev, like what makes it stops so I can hear and count the revs. OK then this is NOT the CSC. It is the pivot bushing or some bearing on the prime shaft maybe? I guess I would also need to open the tranny, not just remove it from the car.

Such a looong first post.. I hope it is not that bad at all. Cheers Z owners!

MicVelo

All transmissions on Z cars including both 33 and 34 are noisy. Especially JK40/41 (07-8 HR application) and EA from Z34. Sounds like a small cement mixer rattling around until you depress the clutch pedal which loads the transmission shaft momentarily, quelling the noise.

The question(s):

- That all said, did you install a lightweight clutch? If so, likely culprit is the transmission input shaft. Normal. Going to have to live with it.

- Is shifting normal? Any issue engaging gears, particularly 1st? If so, then you may have a clutch issue OR shifter alignment is out of whack since you presumably removed shifter to get the trans out.

Unless you have problems with clutch engagement or gear engagement, it's most likely normal.

Just one of the reasons I stick with DMF or an iron SMF (JWT, 26#, a couple lbs lighter than DMF) - which we installed in kid's car and it's a dream. Still hear the cement mixer at idle but hardly anything to be bothered about.

allmightsu

I installed 14lb lightweight fw. Cement mixer/rattling is fine. It came from day first. The "new" sound is the whine. Its loud.. and like 350-400miles after the combo change it wasn't here, just right after yesterday's fun it started to whine.

Gears engagement are all fine. Only a quick 1st to 2nd gear in high revs is grinding. If I wait like half second, then its fine. Low rpms, no issue at all. So the syncs on 2nd gear are gone. Thats knows. But they are like that since I have the car. No related to the lightweight smf.

I am just wondering, would it be that the pivot is pretty bad gone. Having in mind I haven't changed it. To unmount/mount the tranny wasn't that smooth, so surely the pivot buah is not "like new".

Maybe my next plan is to replace the pivot. Quite quick and cheap task. No hurt, just time and physical effort.

But yeah.. at the end if nothing help I will also try to revert my DMF. If that helps I will stick to it. Even it is only a fun car, the whine annoy me sooo much. The rattle - not really.

allmightsu

I recorded a video today.. playing with the clutch, so it could be heard quite good.

Jako81624

Hello mate! Did you ever work this out? Similar noise on mine, only happens when clutch is engaged or when the car is in gear and rolling (but quieter than when the clutch is engaged)

allmightsu

Hello, mate. I fixed it.. partially. At the end it turned to be the input shaft. It was bent, like.. 0.04 or so. Measured on a metal lathe (or whatever is the proper name in English). How exactly did I bend it, I can only guess. Did I do it during the very first removal (I did a stupid mistake) or did I do it cause I drove it with a bad pilot bearing, who knows.

After the change, this exact noise disappeared. But now there is a small whine during load. If I am revving the engine while it is in neutral, there is no noise beside the normal one for the 350z's gearbox. While under load (1st, 2nd, 3rd.. gear), it whines a bit.

I was reading that there are cases of noise after a replacement of the 6th gear synchros, so I am not sure if thats my case also. Because Nissan changed the design of the input shaft it requires a new synchro for 6th gear as well. Same with the 5th.

I dissembled the gearbox twice since then and there is no bearing wear at all. I really have no idea what is wrong. I just cannot understand what part might be worn, there is just no such. All bearings are new, new input shaft, I broke and replaced the gearbox plate, so it is also new (all parts from Nissan). Sometimes I think this plate might be somehow defective or.. don't really know.

It is really not that high of a noise so I drive it like that and most of the time I don't even hear it. But it still drives me crazy, somehow, so I plan to buy a new gearbox from Nissan at some point.

Jako81624

Now that is fascinating - lathe is absolutely the correct word, my guess is you/your machinist threw it on a lathe and measured the runout/concentricity. Did you ever have vibration through the gearstick at certain points in the rev range, most notably when decelerating? I know almost for a fact that my flywheel is unbalanced right now (old, knackered, factory dual mass) so I'm replacing it with a single-mass flywheel in a bid to fix that in particular, and I'll be replacing the pilot bearing with the NISMO roller bearing instead of the factory copper bushing like you mentioned. My (completely wild) guess would be that the dual mass flywheel could've been unbalanced and thrown the input shaft out of round and, with that extra weight removed by replacing it with the lightened single mass and the subsequent reduction in damping, the sound was exacerbated. Did you replace the input shaft bearing (having reread your post I think you did)? That would have been my next guess and is one of the replacements I've potentially got earmarked for mine.

In my case, the sound isn't as aggressive as yours in the video and I'm still trying to work out where it's coming from. When the car is moving and out of gear, there is no sound. With the clutch depressed, there is no sound in any situation - which should eliminate the CSC. When the car is in gear, rolling and with the clutch still depressed the whine comes back, but only quietly. It gets progressively louder the lower the gear, so the action of moving the shift collars over the constant mesh gears that are tied to the speed of the input shaft is what precipitates the noise. There whining in neutral is there but isn't quite as loud, but I will be checking that tomorrow just in case. I'm leaning towards it being something on the input/counter shaft since there is only ever noise with both the output and the input shafts engaged simultaneously but not when just the output shaft is spinning. It could be something as simple as the fact that when the shift collars are engaged there is just enough mass on the input shaft to place a load on a bearing somewhere on the output shaft, or even simpler still it could just be gear whine from the constant mesh gears. With just the output shaft spinning they wouldn't be moving, but when the shift collars engage it would tie the input and the output shaft together and put those gears in motion. You can probably see the thought processes going through my head as you read this post, and having written it out I'm now more convinced that it's gear whine from the constant mesh gears. I'll put a video on here ASAP for you to compare yours with sometime, and if they sound the same then I might look into aftermarket gear sets. Could just be low-tolerance gears from the factory. Aside from that, in the (very, very) long term I'm planning on going sequential anyway so I might not worry about it too much as long as the gearbox holds up! Just like you it does annoy the **** out of me though, even if it is fairly quiet in the grand scheme of things. It might just be another one of the foibles of the Z that we have to put up with . My car is an 08 HR, thus with the JK series transmission - what's yours?

allmightsu

Sorry mate, I couldn't get to the PC to write a reply. The way you are describing it:

1) Eliminate the diff and the bearing on the output shaft. As it rotate with the wheels/diff/propshaft, it should be fine as the car doesn't wine while moving and out f gear;
2) Also should eliminate the small bearing between the input and counter shafts. There is a needle bearing between them which also should be fine;
3) You have 3 more bearings one on the input and two on the counter shafts. None of them is hard for replacement if you have some experinece with this and a nice garage. There is an amazing guide in internet for those transmissions - step by step.

In any case I would reject an issue with a gear wheel (the needle bearing there), because if an exact gear is whinning, it would stop when that gear is engaged.

By the way mine doesn't wine that aggressive anymore. Now it is way way less, not like in the video. But it still drives me crazy. Yes, I replaced all of the gears even twice. Before replacing the input shaft, I replaced the bearings one by one as I wanted to be sure that I am on the right way. Once I replaced the input one, car got quite for like 40 seconds.. which made me believe that the input shaft is bent. Then went to the machine shop, etc, etc.

So the whine on the video is from the inputshaft bearing but because the input shaft being bent and puting a lot of stress on the bearing.

Once the shaft got replaced, there is no such aggressive noice, just the one under load that remained.

Last time when I dissmantled the gearbox to examine whats wrong.. well, everything looked fine. No visual wear and no wine in the bearing when spun by hand.

No, I didn't have any vibrations on the stick, no harsh enagage, anything but the noise.

I am also not sure if a NISMO pilot bearing is better than the bronze one. I guess that the needlе one would require servicing/lubrication. The problem with my pilot and the box was caused by me, but that is a long story. I am getting mad that I cannot fix it even I replaced half of it. I am missing something really st*pid or it is a design issue after replacing the shaft and synch with the improved ones.