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?