2nd gear clunk, rubbing, grind

daisuke149

I would double check the 3.1 wuarts thing!

im almost 99% positive but dont hurt to ask

spinhead

Changed tranny fluid this weekend. 2nd gear is still a b!tch, no noticeable improvement. Could it be the 2nd gear synchro? All the other gears are fine.

Overall the transmission does shift more easily now when warm so that's good i guess. I had them use a 50:50 mix of Redline MTL (70w80) and Redline MT-90 (75w90)

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Consequences will never be the same.

fuct

mixed the oils?????? is that even safe?

spinhead

DIY: Transmission Oil Change

7. Place the inlet hose of the siphon pump into your fresh container of oil. Start pumping...you'll notice it takes a bit of work to pump the viscous oil up into the transmission. The capacity is 3 quarts and I used a 50:50 blend of MTL and MT-90 since I live in Chicago and experience the hot and cold extremes. The mix will get you a blended viscosity close to Nissan's recommendation of 75w85 (MTL is 70w80 and MT-90 is 75w90). Pump until oil starts leaking around the pump hose from the filler screw hole.

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Consequences will never be the same.

Jeffblue

That's because you're granny shifting and not double clutching like you should.

daisuke149

I understand the mixing but the new mt-85 is actually perfect for the tranny. no longer need to mix.

Rash1

Same thing with me, when I shift faster it works 100%.

cooperreese

Hey Guys....
I read all your posts and I have the noisy, clunky, 6MT on my 2009 370z Base model as well....
But mine also grinds into every gear on downshifts. 6-5 is the worst.
It will do this until the PT is good and warm (In my case, thats usually about the first 15min of driving every day).
I have about 25k miles.
I am going to get a flush as soon as I can get the time. But the Mech I took it to said the fluid was dirty and had particles in it.

Now, being an aviation mechanic, darker oil in a semi-closed system is usually caused by contaminants, either metal flakes (minute or not) wearing off gear teeth or they are caused by improper lubricant used in gearbox.
Now, if I have dirt in my system, it obviously got in to the system before I got the car (which I purchased brand new).
I have not been driving around with a dipstick missing or plugs removed.

How the hell could dirt be in the system unless it was in there from tranny assembly at factory?

Thoughts?!?!

vin17

I've had the '14 Z Touring Sport MT for 1100 miles to date.

Here's what I've found:

Shifting at anything below 3K in 1st, 2nd, or 3rd gear will cause the clunking.

Upshifting in normal traffic at 1, 2, 5 and 6 works best for "normal" in city traffic motoring with minimal clunking.

The clunking noise is the synchro and LSD out of sync due to low revs in the lower gears. I'm not sure what the gear ratios are, but I suspect they're high in 1 2 and 3. Higher revs in the lower gears cures all. It's smooth and quiet around >3500 rpms While it's understandable that the Nissan Z engineers designed it as such - it's annoying in slower traffic.

BTW, I checked the differential oil factory fill level at the dealership this week, and it's clear and full with a consistency similar to thin vaseline.

I also had the service manager check with the Nissan "DTM" as I complained at 150 miles about the clunking and mentioned that this forum has multiple threads on the subject, and using different differential and MT fluids - specifically RED LINE. The service manager informed me that NISSAN DOES NOT approve of using RED LINE oils. Of course you might expect that, but this dealership allows customers using their own oils if approved by NISSAN.

I asked them to check if Mobil 1 synthetic LSD was approved.

I'll update this post when I get more info.

JARblue

The dealer cannot deny warranty service if you use OEM-equivalent fluids, so whatever the service manager told you about Nissan not approving Redline is irrelevant. Redline 75W90 gear oil is perfectly acceptable (and highly recommended on this forum).

I use Mobil 1 for engine oil because I can get 5qt for $25 at Wal-Mart. MT, differential, and power steering fluids are all Redline. Clutch and brake fluid is Motul. The OEM fluids are fine for your car, but my research indicates that Redline and Motul fluids are much better (especially if you push your car)

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roplusbee

1. That is definitely not good. I thought the factory fill was supposed to be translucent and brownish red. In either case, I use Motul fluids for Tranny and Diff.

2. That guy is full of crap. I have had Mobile 1 and Royal Purple oil changes at the dealership with no issues or warranty threats. I am currently using Motul to keep everything simple.

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Chuck33079

Holy necrobump. Vin, as long as the replacement fluid is the correct spec, they cannot give you any issues over using non-Nissan fluid unless they provide it at no charge.

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vin17

Update: Mileage 2850

Changed out factory fill engine oil (Mobil 1), differential, and gearbox today at the dealership.
I replaced the factory fill gearbox oil (clean and clear) with MOTUL Gear 300 and the Differential (metal filings present) with Gear 300 LS.

Observations and experience: Gearbox is much smoother with MOTUL than OEM factory fluid - especially downshifting into 2nd and 1st. There is a noticeable decrease in previous clunking linkage sounds. Linkage noises are still there (design flaw) but not as loud, and shifting feels more precise.

Noticeable decrease in Limited Slip slapping/clunking noises, especially from 1st to 2nd.

I attribute these improvements directly to the MOTUL fluids.


I have a long trip coming up next week, so I'll get to feel and hear more over an extended time frame and over the interstates.

Update to follow.

kjz

RJM Clutch Pedal Assembly = shifting is smooth like butter

It was the BEST and first mod I did since I had same issue just like you.
After installing it, no issues at all. Period.

Dsphoto

I've been using Motul 300v motor oil since 5K. I now have 47K, motor doesn't use a drop of oil between changes which I do at 4K. Just changed tranny and dif to motul gear 300 75w90 (ls in the dif). Trans fluid was clear, dif not so much. Thick layer of sludge on the drain plug. Shifting is much smoother and dif isn't as clunky. I wish I had changed out the dif and trans sooner.

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78 Z1R, '08 ZX10R, 2010 BC Roadster S/T, 6M, Stillen G2 CAI, Invidia CBE, Berk test pipes, Painted headlights (180˚Custom), JDM rear fog, B&M short shifter, Stillen front plate mount, stubby antenna, setrab oil cooler, uprev. 337rwhp 254ft/lb corrected!