Nissan 370Z Forum  

Preserving transmission synchros

Hey guys, Whatever manual car I've had has had their related online forums that have a lot of topics on synchros going bad, usually 3rd and 5th gear. On these

Go Back   Nissan 370Z Forum > Nissan 370Z Tech Area > Engine & Drivetrain


Like Tree16Likes

Reply
 
LinkBack Thread Tools Display Modes
Old 02-23-2015, 08:01 AM   #1 (permalink)
Base Member
 
Join Date: Feb 2015
Location: NYC
Posts: 112
Drives: 2014 Nismo
Rep Power: 10
NismoNY is on a distinguished road
Default Preserving transmission synchros

Hey guys,

Whatever manual car I've had has had their related online forums that have a lot of topics on synchros going bad, usually 3rd and 5th gear. On these forums it seems the 5th gear synchros aren't that durable either. I currently have a 2014 Nismo but my previous 350z had a 5th gear synchro issue and it happened first upon a simple downshift from 6th to 5th - from that point on, it would grind every now and then.

So I'm curious, is there an inherent design flaw in the Z transmission, where, over time, the synchros will just start to fail? Is there a reason it's more prevalent in 5th gear rather than 2nd or 4th? Even if the driver is very careful about shifting, is synchro failure still inevitable?

Are there any best practices to preserve the synchros in this car that involve driving habits or maintenance? My car is covered till 2021/100k miles but I'd still like to avoid any problems if I could.
NismoNY is offline   Reply With Quote
Old 02-23-2015, 08:11 AM   #2 (permalink)
A True Z Fanatic
 
2011 Nismo#91's Avatar
 
Join Date: Mar 2011
Location: NJ
Posts: 2,379
Drives: slowly
Rep Power: 33858
2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute
Default

Be gentle with your gear changes especially when ever switching 1st and 2nd gears. A non defective syncro can last you hundreds of thousands of miles if you don't be aggressive with your gear changes all the time. Oh and follow the mfg. maintenance recommendations.
2011 Nismo#91 is offline   Reply With Quote
Old 02-23-2015, 08:22 AM   #3 (permalink)
Base Member
 
Join Date: Feb 2015
Location: NYC
Posts: 112
Drives: 2014 Nismo
Rep Power: 10
NismoNY is on a distinguished road
Default

Are high rpm (5-6k rpm) gear shifts necessarily bad so long as I don't bang into the gear and ease my way into the gates?
NismoNY is offline   Reply With Quote
Old 02-23-2015, 08:29 AM   #4 (permalink)
Base Member
 
Join Date: Nov 2010
Location: Northern VA
Posts: 96
Drives: 05 Elise and 13 GTI
Rep Power: 31
GraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond reputeGraphiteZ has a reputation beyond repute
Default

Quote:
Originally Posted by 2011 Nismo#91 View Post
Be gentle with your gear changes especially when ever switching 1st and 2nd gears. A non defective syncro can last you hundreds of thousands of miles if you don't be aggressive with your gear changes all the time. Oh and follow the mfg. maintenance recommendations.
Do you mean shifting slowly? Mine becomes clunky when I shift slow in low rpm and very smooth when I shift quickly in high rpm. Am I actually doing more harm going slow?
GraphiteZ is offline   Reply With Quote
Old 02-23-2015, 08:33 AM   #5 (permalink)
A True Z Fanatic
 
mag_black's Avatar
 
Join Date: Mar 2013
Location: Massachusetts
Posts: 1,400
Drives: 09 370Z MT6
Rep Power: 666
mag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond reputemag_black has a reputation beyond repute
Default

I use to grind 1st - 2nd every time no matter how slow I shifted. I switched to Redline and I don't grind at all. I find that the Z seems to like slower shifts, or rather unforced into the shift gate.
2011 Nismo#91 and GuiLLoZ like this.
__________________
fujimura ≠ abbeyRoadCompany ≠ fastIntentions ≠ motordyne ≠ avantGarde ≠ ecutek ≠ nismo ≠ stillen ≠ stoptech ≠ gtm ≠ spl ≠ carbonfiberelement ≠ stance™
mag_black is offline   Reply With Quote
Old 02-23-2015, 08:53 AM   #6 (permalink)
A True Z Fanatic
 
Join Date: Aug 2009
Location: N/A
Posts: 76,801
Drives: N/A
Rep Power: 141520
kenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond reputekenchan has a reputation beyond repute
Default

Quote:
Originally Posted by NismoNY View Post
Hey guys,

Whatever manual car I've had has had their related online forums that have a lot of topics on synchros going bad, usually 3rd and 5th gear. On these forums it seems the 5th gear synchros aren't that durable either. I currently have a 2014 Nismo but my previous 350z had a 5th gear synchro issue and it happened first upon a simple downshift from 6th to 5th - from that point on, it would grind every now and then.

So I'm curious, is there an inherent design flaw in the Z transmission, where, over time, the synchros will just start to fail? Is there a reason it's more prevalent in 5th gear rather than 2nd or 4th? Even if the driver is very careful about shifting, is synchro failure still inevitable?

Are there any best practices to preserve the synchros in this car that involve driving habits or maintenance? My car is covered till 2021/100k miles but I'd still like to avoid any problems if I could.
not sure if your 350Z was an isolated issue or not, but usually the first plan of action is to try different tranny oil. my G is 04 and while it was tight in the early days, no issue with grinding. honestly i dont think ive ever grinded the gears on my G over the 10yrs.

hell, i grind my 2.5 yr old honda fit more than my G and Z total years combined (15yrs total)
carlitos_370z likes this.
kenchan is offline   Reply With Quote
Old 02-23-2015, 09:09 AM   #7 (permalink)
A True Z Fanatic
 
JARblue's Avatar
 
Join Date: Mar 2011
Location: Austin, TX
Age: 43
Posts: 36,449
Drives: 11 Z34, 98 E36 M3
Rep Power: 2684440
JARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond repute
Default

I feel like the synchros are pretty shitty in the Z. Sometimes it just acts like a unsynchronized transmission. I skip gears pretty regularly and have found that you just have to be patient with it. I like to shift from 3rd or 4th directly to 6th gear when I'm accelerating to merge onto the highway, but I have to hang out at the 6th gear gate waiting for the engine to slow down to match drivetrain speed. If I don't, it will grind, guaranteed.

All that being said, I hardly ever grind the gears. When I was still learning the vehicle, I had 1-2 grind a couple of times, but those were 100% my fault. And after about 20K miles, I started getting the grind going from 4th to 6th too quickly. Nothing I couldn't control with some practice and basic adjustments to my driving habits. I've been running Redline since 15K miles, also.
axmea? likes this.
__________________

2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed |

Last edited by JARblue; 03-04-2015 at 09:15 AM. Reason: on an upshift the engine slows down, not the transmission... duh
JARblue is offline   Reply With Quote
Old 02-23-2015, 10:16 AM   #8 (permalink)
Base Member
 
Join Date: Feb 2015
Location: NYC
Posts: 112
Drives: 2014 Nismo
Rep Power: 10
NismoNY is on a distinguished road
Default

Is high rpm shifting necessarily bad for synchros even if it was done carefully and gently (not slamming gears and letting the shifter slide into place)?
NismoNY is offline   Reply With Quote
Old 02-23-2015, 10:27 AM   #9 (permalink)
A True Z Fanatic
 
JARblue's Avatar
 
Join Date: Mar 2011
Location: Austin, TX
Age: 43
Posts: 36,449
Drives: 11 Z34, 98 E36 M3
Rep Power: 2684440
JARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond repute
Default

Quote:
Originally Posted by NismoNY View Post
Is high rpm shifting necessarily bad for synchros even if it was done carefully and gently (not slamming gears and letting the shifter slide into place)?
I would say there is nothing gentle about my high RPM shifting. But if done properly, the excess wear is minimized. Hard shifting at high RPMs is always going to wear on the synchros more than normal, casual shifting. But it shouldn't significantly decrease the life of the synchros unless you just do it all the time or do it improperly.

Even though I clearly have some synchros that are wearing as indicated by my grinding when upshifting from 4th to 6th, I have never experienced grinding on a hard sequential shift at high RPMs.
NismoNY likes this.
__________________

2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed |

Last edited by JARblue; 02-23-2015 at 11:00 AM.
JARblue is offline   Reply With Quote
Old 02-23-2015, 02:33 PM   #10 (permalink)
Base Member
 
Join Date: Feb 2015
Location: NYC
Posts: 112
Drives: 2014 Nismo
Rep Power: 10
NismoNY is on a distinguished road
Default

What do you guys consider rpm high for shifting in this car? I've been driving stick for many years and with my past cars I would shift around 2.5k (6k-ish redline). With this car, because of the 7500 rpm redline, I find myself shifting higher... around 3.5 - 4k rpm. Is this bad for the synchros? Again, I'm gently shifting and not forcing the shifter... I just let it ease it's way into gear nice and slow, no fast shifts here.

To me, high RPM shifting is 5.5k+ with this car.
NismoNY is offline   Reply With Quote
Old 02-23-2015, 02:35 PM   #11 (permalink)
A True Z Fanatic
 
JARblue's Avatar
 
Join Date: Mar 2011
Location: Austin, TX
Age: 43
Posts: 36,449
Drives: 11 Z34, 98 E36 M3
Rep Power: 2684440
JARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond reputeJARblue has a reputation beyond repute
Default



This car likes higher RPMs than most MT cars I have experience with. I find myself casually shifting as high as 4K RPMs on occasion. 5K and up is high RPMs.
NismoNY likes this.
__________________

2011 370Z 6MT Sport Gun Metallic | ARC | CJM | Ecutek | FI | Fujimura | R2C | SPL | Stillen | TWM | Z1 | ZSpeed |
JARblue is offline   Reply With Quote
Old 02-23-2015, 04:45 PM   #12 (permalink)
Enthusiast Member
 
Join Date: Feb 2014
Location: California
Posts: 319
Drives: 14 370z
Rep Power: 11
Akurei is on a distinguished road
Default

The Z's transmission comes kind of stiff when you first get it. With some time it will loosen up and be smooth, especially with some redline in it. I like to agree on one thing. The Z with the stock clutch and flywheel takes a little bit longer to rev DOWN when UPSHIFTING gears to match the next gears rpm. I hear you can have faster down revs with a lightweight flywheel. Most likely a performance clutch would help and also more stiff motor and tranny mounts. Not sure about any side effects. Some people complain they hear noise or something with a lighter flywheel.

In regard to a base transmission without Synchro Rev match

Last edited by Akurei; 02-23-2015 at 04:50 PM. Reason: Lots of errors
Akurei is offline   Reply With Quote
Old 02-24-2015, 12:56 AM   #13 (permalink)
MJB
A True Z Fanatic
 
MJB's Avatar
 
Join Date: Aug 2011
Location: Tacoma, WA
Age: 40
Posts: 1,498
Drives: a POS truck
Rep Power: 495
MJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond reputeMJB has a reputation beyond repute
Default

Shifting gears while the clutch isn't completely disengaged will cause wear and tear on the syncros. Like I preached before, its better to go to the floor with the pedal when shifting, especially if you are a newer manual driver. Better safe than sorry IMO. Yes, we all know the true engagement point is about halfway down on the pedal and not the floor... but if the clutch is even slightly still pressed up against the flywheel during a shift, its going to transmit that torque throughout the transmission, and eventually you'll be saying "can't find it, grind it".
__________________
09 Nismo #0483 sold. Viper or C7 next time around.
MJB is offline   Reply With Quote
Old 02-24-2015, 08:43 AM   #14 (permalink)
A True Z Fanatic
 
2011 Nismo#91's Avatar
 
Join Date: Mar 2011
Location: NJ
Posts: 2,379
Drives: slowly
Rep Power: 33858
2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute2011 Nismo#91 has a reputation beyond repute
Default

Quote:
Originally Posted by NismoNY View Post
Is high rpm shifting necessarily bad for synchros even if it was done carefully and gently (not slamming gears and letting the shifter slide into place)?

You'll be fine, quick drastic changes do the most harm. High rpms put a lot of stress on everything, not just your transmission. But, plenty of people track this car getting it close to or at redline often under high load and still have their engine running fine for years now. You can change the fluid the Redline MT-85 or similar if you want the added piece of mind or feel you have similar issues to what people described above.

DIY: Transmission Oil Change
2011 Nismo#91 is offline   Reply With Quote
Old 03-02-2015, 05:54 AM   #15 (permalink)
Base Member
 
Join Date: Feb 2015
Location: NYC
Posts: 112
Drives: 2014 Nismo
Rep Power: 10
NismoNY is on a distinguished road
Default Any truth to upgraded 5th gear synchros?

Came across 2 posts mentioning Nissan upgraded the 5th gear synchros in the later model Zs. Is this true?

2013 Nissan 370z

Sticky: 370Z Transmission Failures (6MT)
"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."
NismoNY is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Transmission problem (?) after a transmission fluid change EWarren Engine & Drivetrain 7 07-28-2014 11:44 AM
6MT Transmission symple84 Engine & Drivetrain 1 07-16-2011 12:00 PM
Another transmission. Solus Engine & Drivetrain 28 10-27-2009 05:14 PM


All times are GMT -5. The time now is 03:44 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 PL2