Rattle-less take offs in 1st hard when hot

Rahul718

Has anyone else had this issue with their 6mt Zs? I'm no stranger to driving stick but with this car I notice that as the car gets hotter (driven around, etc) it's harder to take off in 1st gear without a slight rattle. The only way to avoid this, that I've found, is by revving to 1500rpm or so and letting the clutch out. Alternatively, when I release the clutch really really slow and give gas, the marbles in a can noise seems lessened.

I also DON'T notice this rattle during the first few minutes of starting the car. Which makes me curious if this is a gearbox noise or clutch/flywheel, all of which are stock by the way.

In addition to the car needing to be hot for this to happen, I've also noticed it seems worse in the summer weather when it's really hot compared to the chillier temps. Just curious if this is characteristic of the Z or not.

Joe@ZSpeed

It's normal, Your stock flywheel may be getting worn as well, When the car is hotter the the trans fluid is thinner thus more noise from the trans, It's basically what everyone is talking about when they say "chatter".

You can try some better trans fluid like Redline MT-85 or the Motul Gear 300, Should quiet it down some.

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Rahul718

- I'm actually running Redline MT-85 right now
- Is this really "chatter" though? Isn't chatter when you're in too high of a gear at too low of a speed (ex: 4th gear @ 20mph)? If so, yes, I can reproduce those chatter sounds all day. But starting off in 1st, clutching out, shouldn't give chatter, especially with an OEM setup. I could be wrong...
- Transmission only has 2k miles on it. Nissan replaced it recently. The rest of the car including the stock clutch and flywheel have about 19k on it.
- If I rev up to 1300 rpm or so when taking off in 1st, I can't hear the rattle

Rahul718

^ Anyone?

I was able to rent a 2013 base Z 6mt for comparison purposes. Although mine is a Nismo, I can't imagine they would be too different in regards to transmission behavior minus the SRM feature.

I was able to get the car really hot (around 230 degrees on the gauge) and noticed that the transmission was louder too taking off in 1st. Sometimes it would give off the rattling sound, other times it wouldn't. I still think mine just seems to slightly rattle a bit more. My clutch/flywheel has 5k more than the rental... could the difference be chalked down to that?

Joe@ZSpeed

It is just trans gear rattle, It is caused by the high compression engine in which every time a cylinder fires it sends a pulse through the crank, If the dual mass flywheel cannot absorb it all it will transfer into the trans causing the gear rattle.

The Dual Mass Flywheel is sprung like the center of a clutch, Once this is bottomed out (taking off) it may transfer some of the engine vibrations into the trans. Condition of the sprung section will determine how easy it bottoms out, If it is getting worn, it will be worse.

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Rahul718

Thanks Joe-

Appreciate the reply

Smashley

Aftermarket flywheel would drive you nuts

Rahul718

Actually it wouldnt. The reason it's driving me nuts now is because something tells me an oem setup shouldn't have a rattle to it when occasionally taking off in 1st. At least with aftermarket I KNOW what's causing it and that it's normal

reldas

does this count for autos as well? as mine rattles/chatters taking off in 1st sometimes as well until i hit like 1500RPM

Rahul718

Was really just looking for feedback for the 6mt units but interesting to know it happens to the autos too...I've seen a post about someone else with an auto with the same issue you describe

D.Stillwell

I was wondering about that clutch rattle noise as well when I first got the car. Everyone said it's normal so...

I've learned over a month the smoother you are with that clutch, esp. when going slower and in low gears, it becomes way smoother.

Mine does not rattle as long as you rev to 1k or above taking off in 1st, unless on a steep hill then you need 1500rpm for a smooth takeoff. Its a heavy clutch so its to be expected I guess

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Rahul718

Did you find that this rattle only appeared after the car was driven for some bit and was hot as compared to right after a cold start?

D.Stillwell

You know, I never paid attention to that. I'll try to see if thats true today on the drive home from work.

But I imagine it's probably true as the metal changes with heat. The clutch def feels more raw when cold tho, I can def say that.

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D.Stillwell

^^ Update for ya...

Yeah. It's definitely true. Just drove home, and I made sure to pay attention to the clutch. There was no rattle at first for a while when the car was still cold...

But then came hwy traffic, and thats when I started hearing that rattle. I noticed its directly related to rpm, higher the rpm the less noise.

It happens at low speeds when being fast with the clutch, I noticed that babying the clutch at low speed and being super smooth almost eliminates the rattle completely at times.

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Rahul718

Hey thanks for verifying man! Did you happen to clutch out slowly in 1st when moving from a stop? If so, did you hear the rattle then when the car was hot?

I'm convinced all the Zs do it now, but maybe some more than others