Sticky: 370Z Transmission Failures (6MT)

370Z_RACER

mine is SMOOTH AS BUTTER

DIGItonium

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

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Baer383

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!

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2013 ZL1

754 rwhp 747 rwtq

370Z_RACER

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

DIGItonium

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.

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Baer383

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.

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2013 ZL1

754 rwhp 747 rwtq

DIGItonium

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

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.

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Baer383

Why the hell did you have to have 3 tranmission?

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2013 ZL1

754 rwhp 747 rwtq

BGTV8

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 .....

edub370

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.

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Huck

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

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Huck

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

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Davey

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.

IDZRVIT

You're joking, right? 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.

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"America.... still builds rockets!"
Vette: 355 cid, 400 rwhp
'13 CTS-V Coupe: 6.2L LSA, 556HP

luigi90210

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