New 370Z's 6-spd manuel, weak link???
 

...i love everything about these new Z's, from the 3.7l to the styling... and it appears these new motors will be making mega HP in the near future* ...however, i've heard lots of horror stories of how weak the previous 350Z's gearbox's were and have already read several posts here of how NEW stock 09's are having problems with their 6-spds already!?

I'm looking to build & tune one of these new Z's to over 700RWHP and am wondering what the experts here think regarding how the gearbox will hold up* Is there anything as far as upgrades for these gearbox's?

I appreciate the feedback* :)



~ K.D.

Nearly a hundred views after two days and not a single person has any insight on this???:rolleyes::confused:


Are these trannies basically a direct and close evolution of the 350Z trans? If so, how much will/should they hold before running into huge problems??

There are a few guys on here that might be able to give you a little more insight from a track perspective. To name a few: Mike from DDMotorsports, DannyGT, Semtex, and a few others. They might be able to help with your questions.

ask Stillen

The problems plaguing the manual 6MT's since 2003 have been related to the synchros, not handling additional horsepower. With the aftermarket clutches available, you're good to go on a ton of HP.

Whether stock, supercharged, or crazy twin turbo kit, you can still have issues with synchros..

Gtm is a good person to ask. He turboed a G37 to 600+ hp.
He's on here as a vendor, shoot a PM.

I dont put much stock in what stillen says bro... being you'll just reach a psuedo tech/sales operator looking to push stillen products on you that doesn't relistically know jack about what these cars have been proving to crack. (no pun intented Josh* u r not that type!) I was told by them years ago that my MKIV supra needed a fully built motor for anything above 550HP and he can sell me the parts i need right then and there lol.. They don't build powerful cars anyway... no offense but a ~350rwhp sc kit is BS (powerwise) and thats their primary business...


No, I'm talking about a smaller company (like GTM) that pushes the envelope and probably has many 500-600+rwhp Z's in the past. Or Sound Performance which built a 1033RWHP 350Z a year ago with twin billet 6262 turbos... what have they seen with these trans's?? ...I will build her to over 700RWHP and need to know if the trans can easily take that in hwy and road racing ventures...??

^ I just said GTM.....LOL

You posted while a was writting my post hence i didn't see it lol... thanks brotha ;) Anyone else?

Altered Atmosphere were the first ones to TT the 3.7L engine.
Look around for them on the homepage

Manuel? Who is Manuel? Paco's cousin?

^ funny guy

:icon18:

As probably the only person in the country that has had his 370z transmission replaced due to bad syncros, I can say that this sould NOT prevent you from buying the car. The real issue comes from blasting up the road through second or third and then shifting over to sixth. Don't do that if you are paranoid.

I don't believe skip shifting was really the problem. That was just a line from your dealer or Nissan and it doesn't make sense with how a transmission works. If anything, skip shifting, done properly, *saves* wear (which I assume is why you were doing it).

While you're a it, see if GTM will post here. Might be a nice read for anybody who still has nagging doubts about the gearbox.

No, actually that is not how it works. The syncros were putting in a lot of overtime to keep up with matching the input shaft speed. They simply wore out from the abuse, which they were not designed to take. You can have the same issue in just about any car you do this in. While I'll admit it happened rather quickly on my Z, it was not completely unexpected nor unexplainable.

Hmmm, I posted in a similar thread about this and I have to say it again, skipping gears shouldn't have any adverse effects on your transmission. Maybe, MAYBE, the syncros but not the transmission itself. I have been skipping gears for over the last 9 years in cars from 5spd to 6spd and have never had any issues.

I assume when skip shifting that you are giving the transmission a moment in neutral to let the revs die down. In other words, you're not trying to speed shift a skip shift (fortunately, H patterns make that inherently difficult).

A correct upshift will not wear the synchros at all. You put in the clutch, put the car in neutral, pause (momentarily) for the revs to drop to the level of the next gear, and engage the new gear. With a light flywheel, there is basically no pause. With a heavy flywheel, and a large jump between gear ratios, the pause is longer. When skip shifting, the ratios are further apart, so you pause even longer. If done right, it ends up just being a nice relaxed (but not too relaxed!) shift.

You know you've got it right because the lever should want to slide right into the new gear. You can tell you're using synchros when you have to press on the new gear for a moment before it "lets" you in.

So you're both right: speed shifting and skip shifting together will damage synchros. Gentle skip shifting should never be a problem.

To get back on topic...

The 6 speed gearbox has been able to handle power just fine. A couple of people have had problems with actually breaking gears, but I would not consider that the norm. Those folks(like Alberto) abuse the transmission worse than even the average enthusiast.

However, the stock clutch will not hold up very long at all. In fact, the stock clutch won't hold up at stock levels if you drag race often. The clutch in my 05 lasted ~25k miles, but that included about 150 passes down the 1/4, all with full throttle upshifts and mid-rpm launches.

Also, since the intro of the HR, Nissan has had problems with the integrated slave cylinder within the transmission. Here's a thread on another site that may be of interest:
http://my[remove]350z[remove].com/forum/vq35hr/428616-bad-news-for-hr-owners.html