Possible Nissan OEM clutch system issue - Everyone Read

NewYorkJon34

Speaking of which, any progress on an upgraded master cylinder?

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FromG2Z

Yeah the Z was not my first sports/sporty car. I've had an Integra, RX7 TT, G35, and then the Z. The Z was by far the worst tranny. I have NO idea why. The G35 I had, was a 2003, it was notchy, but it was in no way like this Z. I don't know how Nissan can revert backwards... makes no sense. Makes me wonder if I had a car that had tranny issues? Mine didn't have a lurch at all, but just that rattly, grinding sound that was so annoying, esp when driving with windows down. I heard it all the time when slowing to a stop or starting to move from a stop. After much research and talking to fellow Z owners, I guess that was supposed to be "normal".

When I had buddies in the car, they'd say, "what is THAT sound?". I'd say, oh it's normal!!! They say, "Oh really???? ummm ok..." Kindda embarassing...

I agree Digi... kindda same thing with an oil cooler. Add it on, even as an option, I'll pay for it.

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ChrisSlicks

There's nothing really wrong with the tranny, the problem is the slave. Nissan made the switch in 2007 to the CSC instead of the traditional slave with clutch fork to save money. There has been nothing but problems ever since. Nissan is doing a pretty decent job of sweeping the problem under the rug to avoid a recall, then again a recall usually requires a solution - which they don't seem to officially have yet. Dragging clutch causes all kinds of problems including notchy engagement, grinding, and premature clutch wear. Also failure is a serious replacement task where as the external slave was a simple bolt on affair.

They had a recall at the beginning of 08 for some of the problems the 07's were having with the slave.

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DIGItonium

Then you've got owners like me, who have aftermarket clutch, flywheel, and CSC. It's great, but the 1st gear lurching and clunking is there. That can be avoided by being a little more patient getting in 1st. Then there's the intermittent notchiness where it literally takes more muscle to get in and out of gear. Bleeding the clutch fluid helped quite a bit, so the problem is not as frequent as before. However, I find myself getting stuck when parked in gear on a slope.

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ChrisSlicks

Sounds like the CSC doesn't have quite long enough of a throw for your aftermarket clutch. What CSC did you use? Did you use the spacer?

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DIGItonium

It's the ZSpeed HD CSC. The only modification is to the transmission cover to fit the new CSC.

If that's the case, is there any way to adjust it so the CSC pushes further? Would it be related to adjusting the clutch pedal engagement point in the 350Z?

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ChrisSlicks

I guess it depends on where the real problem lays. What clutch did you go with? Z Speed has a bearing sleeve that fits over the CSC that extends it's reach so to speak, with some clutches the CSC doesn't make good contact with the fingers of the pressure plate.

350Z HR High Rev Concentric Slave Cylinder bearing adaptor sleeve
New product review: CSC bearing sleeve for aftermarket clutches

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DIGItonium

I ordered the ZSpeed CSC and South Bend DXD Stage 4 as Joe recommended.

[EDIT] The car is still "drivable." There were a few times I got stuck in 1st, so I eased the car forward a bit and was able to take it out of gear. I tried to see if the car would budge or checked the tach with the clutch fully pressed. No difference, so it appears the clutch is fully disengaged. Again, the problem comes and goes. When it doesn't happen, the gearbox is very smooth (knock on wood).

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DIGItonium

Update... I just got the car back from service after replacing the rubber boot that covers the shift linkage.

The tech was able to duplicate the sticky gearbox issue by getting on an uphill slope and even backing up the car. He also noticed a bit of judder that comes and goes. He spoke with one of the GT-R master techs and he noticed that I'm running DOT5 fluid (Module RBF600). So the possible causes for the gear getting stuck is possibly the DOT5 fluid not being up to temp and clutch disc (as esfourteen mentioned).

Again, the car is still drivable and this issue does not appear to grind gears. I'm told to keep driving, and to take it back if it gets worse.

I found a thread in the Challenger forum in which owners had the same issue. There were mentions of some sort of shift rail, detent ball and spring, etc., that might be causing the hang up.

Whatever it is, hopefully I can get it covered under warranty.

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esfourteen

Its the southbend clutch disc/pressure plate combo. I'm using the Zspeed CSC and dot 3 fluid and it's 100% normal with the stock clutch, so clearly there is enough travel here. With the southbend it had a hell of a time getting the car into gear 80% of the time.

The clutch is going back to southbend and hopefully they can explain why this is happening.

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DIGItonium

Thanks for the heads up. When did you order yours? Mine was in Feb. this year. You would think there would be enough testing to ensure this sort of issue doesn't happen.

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DIGItonium

I just sent a message to South Bend. I let my friend test drive my car today, and we also drove around and did some test runs. Almost all of the time we were unable to get into 2nd at full throttle, and it grinded very badly! Afterwards, it was difficult to get into any other gear so we had to take it easy for awhile.

Today was pretty warm as well, so I wonder if heat is causing issues with the South Bend clutch.

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Perfourmance

shame to hear...with this issue and the natural overheat tendencies I'm considering something else

I recall the notchiness in my bro's 350 and a buddy's g35 but this sounds worse. I miss my AP1 gearbox!

DIGItonium

The gearbox isn't the best out there, but it's much better than the one in my 350Z. The only reason why I'm having issues is from the upgraded clutch. I should be able to resolve with with some adjustments and more miles.

However, it is true that the master and slave cylinders are fairly weak, but the 370Z is not the only one affected. I'm running an aftermarket slave and am waiting for an aftermarket solution for the master cylinder. There's one in the works for DE/HR, but VHR has an ABS module that interferes with the installation.

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Perfourmance

If you had to do it over again knowing what you know now about the drivetrain, would you still buy the 370z? I'm trying to decide between the standard: 370z, Evo X, STi