Sticky: 370Z Transmission Failures (6MT)
 

Let's sticky a thread that lists owners who experience 6MT transmission failures. We'll list part numbers here in case Nissan decides to rev the part number. Hopefully we can gather some failure stats. Nissan pretty much needs to do something about these craptastic synchros.

• ID: 320B0-1EA0B
• Purchase Date: 04/17/2009
• Type: Sport

Replacement #1 (05/18/2012)
I started having 3rd gear grind that progressively got worse. It would be fine early in the morning, and then it would grind above 3k RPM. As it got worse, it grinded all the time. Also, the high RPM 1st to 2nd shift and 2nd to 3rd would grind or lock me out. Gearbox was pretty notchy as well. The transmission was replaced along with a new ceramic clutch disk, master cylinder, and a revised HD CSC.

Replacement #2 (08/30/2012)
A month after the replacement I notice 5th gear was a bit difficult to get into half the time regardless of load or RPM. I thought it was normal notchiness, which is nowhere near as bad as the original transmission (all other gears are smooth). Interesting enough, SynchroRev would rev up twice before I was able to get into the gate. The summer has been pretty hot so I've not driven hard as often, nor have I been out to the strip. There were times it wanted to pop out of gear. Then 2nd started grinding and locking out at high revs. I replaced the fluid with Redline, and it smoothed out the gearbox nicely. However, it didn't help with the occasional 2nd gear grind at high revs or 5th gear lock out. Although it never grinded, the 5th gear lockout was getting worse. My tech took it out last week for a test drive and freaked out when he had trouble down shifting into 5th while exiting the freeway. He couldn't force it in at all as if the synchros weren't there, so a new transmission is on order for this week.

I also went ahead and ordered Motul and Redline fluid for the clutch and gearbox.

[Update] New transmission installed with fluids. This gearbox feels very different. It is not notchy, but there is more resistance and you can feel the gears. There is slight whine in 2nd. Although I am able to shift well now, I miss the buttery ease of the last transmission. I'm going to let it break in and see how it goes from there. part number is the same.

jeeze... sorry for your troubles. Nice thread... hopefully there won't be too many bumps :ughdance:

I now have the crunchies on skip shift from 3rd to 6th at max-revs (like accelerating the car up to speed on the on-ramp to freeway and then slot into 6th at 110kph). Car has 70,000klics on it. So far, only 6th affected.

Have gone to Motul gear oil and is "better" but not perfect. I have an extended drivetrain warranty (up to 150,000 klics) on my car and will be hassling Nissan about it at the next serice, but the car has seen a lot of arduous service (track days and speed events) so I'm optimistic about a Nissan repair .. we'll see.

I got a bad crunch going 1st to 2nd at high revs. I'd bet I have transmission troubles, I'll have to do more testing first. Is this covered under the extended power train warranty?

The 1-2 shift at high RPM is terrible. It is a hit or miss. My tech couldn't nail it either, and it was easy when the transmission was new. It literally locks out and grinds half the time to the point my hand would slip off the shift knob. Before the last transmission was replaced I didn't recall having a successful 1-2 upshift. 3rd would lock out and grind until the revs went down to 2k or so. Even if I did get in 2nd, it would grind going in.

One of the members here had his synchros switched out for ones sourced from Ford Racing, and it shifts like a champ. However, it is currently cost prohibitive which is around $2k. Maybe someday... but not after getting my own pad haha. I don't even have sod and sprinkler in yet.

Do not skip to 5th or 6th gear on the Z. It is known to have weak 5th and 6th gear synchros. You will wear out the synchros.

Yes. It is covered to 60K miles... It's not a wear item, it's part of the powertrain, fully covered!

Good to know, thank you sir :tiphat:

If you beat on your tranny, don't know how to shift (yes, there are some in here) or add lots more HP/TQ it will probably have issues because it wasn't designed for that. I don't have any issues except the odd clunk and it shifts as well or better than any manual I've ever owned even at redline. But mine is not FI. By comparison, my 2011 Civic's MT/clutch is a pos compared to my Z. You get what you pay for.

Well known that the Z has crappy synchros.

They toughened up the 5th gear synchro in mid10 and again in early 11. By all measures the mid11s seem to have dramatically better 5th gear behavior.

I occasionally grind 1st to 2nd but I attribute that to lack of attention rather then the syncro because its not consistent. Pretty much happens in all my past cars.

I don't see an issue skip shifting if you give the time to match revs.

I'd like to know with what people have had problems do they have SRS?

I doubt SRS has anything to with it. All its doing is revving the engine to make a smooth downshift which is a benefit if anything by reducing stress. Now if there were some mechanical linkage then there might be a cause for concern but there isn't. It's all electronic. No car is bullet proof. If you beat on it beyond its design parameters its gonna break. Open up your wallet and don't expect the warranty to cover it.

Haha I don't beat on my car that much even with FI. I haven't even tried dumping the clutch or drag race. The summer heat has been a record breaker so I don't get to drive as hard. My car has lots of freeway mileage. Plus 5th isn't even a gear I would race in. It's just a daily driver to and from work. My tech knows I baby this car lol.

Downshifting into 5th during normal driving can be a pain. It's hit or miss really. SRS is always OFF.

Is this tranny used in any other Nissan/Infinity model? If so, are there other complaints?

mine is SMOOTH AS BUTTER

I got the new transmission installed yesterday. It feels very different than the others. Going to let it break in.

This the stuff I use in my Harley trans and it not nearly as clunkly,I will use this on my 6sp when I change it.

Red Line Oil Heavy Shockproof Gear Oil (58204) on eBay!

if your transmission goes, you don't know how to drive

If you post stupidity, you don't know how to drive.

I grind from 1st to 2nd sometimes at higher rpm. At first I thought I wasn't clutching all the way so I made a conscious effort to go all the way to the floor. Still happens. Same thing, skip shifting is sketchy. I took it to the dealership a few months ago, they "couldn't recreate the problem". I'm taking it back again soon.


Sent from my iPizzle using magic and new-fangled science stuff

Huck, I've come to accept the fact that the high RPM 1-2 shift is a hit or miss. With the other gears I don't completely take my foot off the accelerator pedal, and I can achieve some fast high RPM shifts. As long as I can daily drive without the 5th gear hiccup, I'll be fine. Everything else is smooth now.

You're kidding, right? I'm a smooth and fast shifter. Explain to me how I know how to daily drive a twin turbo 370Z. :rolleyes:

I've learned from past experience that the more power you have the harder driving a stick becomes,so I imagine that a twin turbo would be hard I'll let you know after I put my SC in.:icon17:

Your opinion means nothing until you get back in the FI'd club. :icon17:

Seriously, though, that's not always the case. With daily driving, the car is pretty much stock since it is hardly in boost. When I'm in boost, it's typically half throttle around 3-4k RPM. That's usually when I'm getting on the freeway or trying to catch up in traffic.

The 1st transmission endured more punishment. With the 2nd transmission, I only had it for 3 months and it did not endure much punishment due to extreme hot weather over the summer.

What's interesting is the gearbox for all 3 transmissions (including the original) feel quite a bit different. The newest one feels so might tighter, and there is slightly more resistance. It's not notchy, but I can definitely feel the gears or something. What I find different is a noticeably louder whine in 2nd that I didn't hear before with the other transmissions.

So far no issues getting in any of the gears. No notchiness.

Why the hell did you have to have 3 tranmission?:shakes head:

I may have to accept that, but it just upsets me that in my civic, mustang, and miata I could power shift all day long with no problem, but in the most expensive car I've ever owned its pretty much impossible. How the he k are you supposed to get good times on the 1/4 mile if you have to baby the stick??



Sent from my iPizzle using magic and new-fangled science stuff

Plenty of people are having issues with the GT500, Boss 302, Mustang GT, Camaro, Corvette, etc. power shifting it and/or just shifting it fast. I would say to some degree it's that these manufacturers have little experience with building a transmission that shifts reliably at 6,000+ RPM, and to some degree, it's cheap **** that seems to work OK for the test drive and/or the first 10,000 miles.

The first one is stock. I'm on my 2nd.

I'm sure it is known the Z transmission does not like super fast shifts. I went through the same ordeal with the '03 350Z.

I rarely grind from 1st to 2nd and that was because of human error(only happened twice)

I don't drive it to hard though and when I do, I don't have any problems unless I'm being stupid

You're joking, right?:ugh2: I think however, that plenty of people are having issues with how to drive a manual. Just read the posts. They're everywhere. See my vette? It has the original B-W ST-10, if you know what that is, and I shift hard all the time with it. 90000+ miles and it's never been apart. So don't come in here and say that the American auto makers don't know how to spec a tranny. My Z roadster with the 6 speed, I have no problems shifting in any gear at 7500 rpm. So, did I get the only car that has a good manual? I doubt that. A guy goes through three trannys and claims there are issues with the it? Not likely. It's abuse or lack of shifting skills.

Um. No? What's there to prove that I can't drive a manual? It's a daily driven vehicle. It's not rocket science for the past 10 years of driving a manual. How the heck can I screw up 5th? It's not even a gear to drive hard in.

The first transmission failed after the clutch disk fused to the flywheel. Part of that problem was due to a defect in the aftermarket clutch disk that made it difficult to get in and out of gear. After fixing the flywheel and getting a new disk, 3rd gear (last gear it was stuck on) started to grind whenever RPMs exceeded 3k. The grinding got progressively worse, so I ended up getting a new transmission.

I did a few tests, and the car drove great. Then I dealt with record heat all summer, so I didn't get to drive the car as hard. Even if I wanted to drive it hard it's as easy as flooring it while in gear. What's so hard about that? After a month I notice difficulty getting into 5th. It took more effort than usual to get it in gear. All the other gears were buttery smooth. So I ignored it for 2 more months as it progressively got worse. Replacing the fluids with Redline didn't help either. My tech took it for a test drive and had issues getting into 5th as he was exiting the freeway and suggested the replacement.

So the one I have now is about 2 weeks old, and it's doing very well.

This thread is to share experiences with failed transmissions, not about who can or can't drive a manual. If some of you don't have anything valuable to contribute, then :gtfo2:

Big call .... I have been involved in competetive motorsport for 40 years, raced 500cc motorcycles in the 70's and sports cars for the last 30 years.

I have 70,000klms on my Z34 and I have a problem with 6th gear syncro. Started after the 5th track day and the root cause I believe is transmission oil temperature related - it may be exacerbated by a lack of mechanical sympathy over time, but I can only report my experience which is that in my car, it is now possible to consistently "beat the syncro" on a skip-shift from 3rd gear and max rpm into 6th .... unless I wait for syncro-rev to sync the rpms, I can consistently beat the syncro's. Even 5th to 6th need to deliberately slow-paced (not condusive to a good lap time I know, but just another problem to drive around).

I agree - for one owner to have had 3 transmissions, there may be an element of lack of mechanical sympathy involved .... especially if the clutch driven plate was "fused to the flywheel" - sounds like the vehicle is subjected to arduous service, but don;t accuse the guy of not being able to drive - he may simply have a different definition of what Mr Nissan's transmission product should be able to tolerate.

I have a 6-speed straight cut gear and dog-engagament box in my race car (from Holinger Engineering - they do boxes for 996 GT3 RSR, the M3 GTS and up until this year supplied the V8Supercar control transmission), and given its level of engineering, I still strip it every 3 seasons (5000 race klms) to crack test the gears, replace bearings, dogs and oil pump bits because in that time it will have been subjected to ~160 race starts and around 2-3000 flat shifts.

Now if the originator of the thread beleives Mr Nissan;s transmission ought to tolerate that level of work, then maybe his (or her?) expectations are never going to be met, but I think accusing him (or her) of not knowing how to drive may not be the most positive point made on the thread .....

Like I said, it culd simply be a case of different expectations ... the NISMO Race Car comes with the same gearbox in the roadie, and NISMO "lifes" the box at 5000klm. So if a box is subjected to race-type service demands in a roadie, them maybe 3 transmissions is actually a predictable outcome as the "in service" requirement is outside what Mr Nissans designers have catered for.

All I know is that the OEM transmission in my car is exhibiting signs of syncro wear after 70000klms and that for me is a sign of arduous service (it has done a lrge number of track days) .... I'm now fiddling with oils to see if I can get some more mileage out of the box before I pull it out. If I do pull it out, I'll have the think about what it gets replaced with.

Making a statement like "3 transmissions = don;t know how to drive" is not logical - there are lots of other reasons behind "why".

BTW - if you read the signature - the car is a TT, so the box is being asked possibly to tolerate torque loads beyond its design limits - most TT kits that run more than 4-5psi boost are going to put at least 50% increased torque demand on the transmission ..... and if the guy is running more boost, the problem wil be worse .....

Hehe who knows about the extra power involved. It tops off at 380 ft-lbs right now. For daily driving it doesn't see much more than 2 PSI during the week. I'm pretty sure if my engine is taking a fair bit of abuse then my engine would have popped by now (knock on wood).

The original had to do with an issue with the aftermarket disk having too much marcel. It felt like the disk was constantly rubbing on the flywheel making it difficult to shift. Of course none of us realized that until the first day at the drag strip that I barely got out of the hole in 1st when things got worse. We pretty much attribute it to overheating from the 1hr wait in line with the stop and go traffic. Several times I had issues getting in gear.

The first replacement was fine, but I barely had it for a month when I had issues getting in 5th. It wasn't notchy. Half the time it took more effort going in, but never grinded. It got worse the next couple months which is when my tech tested it and decided on the replacement.

He doesn't think it was built quite right.

Just because I'm running turbos doesn't mean I abuse this car. It is my only vehicle and it is a daily driver. I pretty much baby this car. There are others running boost and drive it like it's stolen with no problems whereas I'm driving it to work on the freeway everyday. The only time I took it to the strip was when the clutch failed, and it has been 8 years. The 350z only been to the strip once.

[EDIT] Got word about my 3 month old transmission. Hopefully I can get a hold of it for synchro upgrades.

My '09 6MT Base model transmission was recently replaced (warranty) due to a bad 5th gear grind - the new box shifts very well, and schnucks right into gear quickly. However, I also noticed a new whine in 2nd gear. Perhaps this is just a result of beefing up some parts.

--ZOM

Do you notice the part number is the same? Either that or inconsistent build quality.

The receipt shows only 1 part number - not sure if it's the new one or the one that was replaced:
320B0-1EA0A

--ZOM

So it lasted 3 years in stock form and 4 months after you put in the new fluids and clutch and HD CSC? Sounds like keeping a stock trans and fluid in there would be the best right??

No direct correlation. 5th was tough getting in after a month. I tried redline for a few weeks before the tech decided to get the transmission replaced. Shift effort was great, but 5th wasn't getting anny easier. It snags every other time. My current one is running redline since it was installed. It is doing well so far.

You're an idiot...




for those of u thinking this is "driver error" u are mistaken. i have never owned an automatic car in my life. heck i have a manual volvo running twice the boost as its set at from the factory, it has 165,xxx miles on it. it has the stock trans, STOCK CLUTCH, and has never ever had a probelm with either. mind u, that is a car with about 310lb ft of tq. had an 87 944S with 200k on the clock and NEVR had a trans problem even after going thru 2 clutches. 25 year old car... 200,000 hard miles... rwd...

now, i have had the z for about a year and a half. bout the car with 15,XXX miles on it. at about 20,000 miles the 5th gear synchros starts to go. trans has to be replaced. so either i completely cant drive a manual for 5000 miles, or the z's synchros have a problem.

Also, it SHOULD NOT MATTER if u skip a gear on a transmission. been doing it for 80,000 miles in my volvo and that trans is as smooth as butter (even after some abuse). still fine to this day. synchros do not know which gear u came from... all they do is match rpm speed. a synchro does not see a gear coming and go "mother of good... that thing is spinning 500 rpm faster! i can't handle this!". also, a synchro doesn't have anything to do with tq or hp levels. it simply matches rpm speed. so tt or sc should (theoratically) not cause synchro failure. but clearly there is something wrong with the design of the synchros.

its amazing how people have been skipping from 3rd to 5th since the invention of the 5 speed transmission yet every trans in the world hasn't need replacing.... yet when it happens on a z it "is a driver error". c'mon now. its well documented that we have synchro problems.

I lost second gear today, woot! just under 20k. 5th gear syncro would grind when cold as well. MAN DOWN. I know the guys at the local dealer so hopefully they do not give my any crap because I have a SouthBend clutch and CSC, if so, a fight they will have! This trans has always been clunky from the time I got it, nissan could never get their manual right or CVT or...

Agreed. No CVT. For awhile I'd see a car getting a new CVT whenever I went in for an oil change. This included the new pathfinder.