Reinforcing the 6MT transmission

NissanZ34 · 01-18-2020, 10:23 AM

Hello fellow Z owners. My car has about 50 000km and 4th gear is starting to show wear signs such as being clunky when shifting and not being smooth.

Is there a way to bullet proof the manual transmission? I don't want to buy another OEM transmission that will fail the same way over time.

It's a street car but I'm hard on it. I like speeding and found out my car was speed limited at 240 kmh in 5th gear. Would there be a way to remove the speed limit at low cost? (The dealership is a relative and probably told the mechanic to put the limiter)

Modifications done so far:
I already have a Stage 2 clutch kit with the lightweight flywheel from Zspeed along with their CSC delete kit. GReddy GT Evolution catback exhaust and Fast Intentions HFCs are on the way. Also have a Mishimoto oil cooler kit. K&N drop-in filters with Mishimoto silicone intake tubes.

Sport and Touring package

Thanks

crazy4oldcars · 01-18-2020, 11:44 AM

150mph in 5th sounds about right. I think you hit the RPM limiter, not the speed limiter. Top speed is supposed to be around 165 mph (~265 kph).
I have heard tales of people having their 6 speeds rebuilt with Ford synchro's, making them more durable. A search in the tech part of the forum would reveal more on that. Haven't needed the info, so I haven't researched it. From my limited reading, the rest of the transmission seems to hold up well.

Kirk B.

Spooler · 01-18-2020, 02:16 PM

Nothing really out there in the aftermarket world for our 6MT's. Just get a brand new one from Nissan and don't miss any shifts or abuse it.

SouthArk370Z · 01-18-2020, 03:18 PM

No transmission is bullet-proof - if you abuse it, you're gonna break it. The 6MT is pretty stout - some people on this site are FI'ed and running stock 6MTs with no problems. You should be able to find more than one thread on this site about beefing up the 6MT (IIRC, there's not a lot you can do) and how to use the 6MT properly. Personally, I'd get a reputable shop to rebuild the trans; might be able to find some beefier synchros to put in there.

The speed/rev nannies can be adjusted when you get your tune.

Spooler · 01-18-2020, 05:58 PM

Quote:

Originally Posted by SouthArk370Z

No transmission is bullet-proof - if you abuse it, you're gonna break it. The 6MT is pretty stout - some people on this site are FI'ed and running stock 6MTs with no problems. You should be able to find more than one thread on this site about beefing up the 6MT (IIRC, there's not a lot you can do) and how to use the 6MT properly. Personally, I'd get a reputable shop to rebuild the trans; might be able to find some beefier synchros to put in there.

The speed/rev nannies can be adjusted when you get your tune.

LOL, this is true. No issues with 824hp at the wheel. You just have to drive them properly.

Rusty · 01-19-2020, 12:20 AM

There was one member who was redoing the trannies. But he hasn't been on for a few years.

The Z is speed limited to 155 mph. To remove it. You have to use UpRev, or Ecutek tuners.

BettyZ · 01-19-2020, 02:13 AM

Quote:

Originally Posted by Rusty

There was one member who was redoing the trannies. But he hasn't been on for a few years.

The Z is speed limited to 155 mph. To remove it. You have to use UpRev, or Ecutek tuners.

Zingston does trannies every day?

Sent from my SM-G955U using Tapatalk

jchammond · 01-19-2020, 04:18 AM

Quote:

Originally Posted by BettyZ

Zingston does trannies every day?

Sent from my SM-G955U using Tapatalk

Rusty · 01-19-2020, 02:16 PM

I'm disappointed.

There's nothing about Jar in the tags.

NissanZ34 · 01-19-2020, 05:00 PM

Quote:

Originally Posted by crazy4oldcars

150mph in 5th sounds about right. I think you hit the RPM limiter, not the speed limiter. Top speed is supposed to be around 165 mph (~265 kph).
I have heard tales of people having their 6 speeds rebuilt with Ford synchro's, making them more durable. A search in the tech part of the forum would reveal more on that. Haven't needed the info, so I haven't researched it. From my limited reading, the rest of the transmission seems to hold up well.

Kirk B.

No I still had about 100 rpm before hitting the rev limiter which was set at 7600 rpm by the dealership. It was speed limited because the speed and rpm wouldn't budge.

Thanks for your imput.

NissanZ34 · 01-19-2020, 05:07 PM

Quote:

Originally Posted by SouthArk370Z

No transmission is bullet-proof - if you abuse it, you're gonna break it. The 6MT is pretty stout - some people on this site are FI'ed and running stock 6MTs with no problems. You should be able to find more than one thread on this site about beefing up the 6MT (IIRC, there's not a lot you can do) and how to use the 6MT properly. Personally, I'd get a reputable shop to rebuild the trans; might be able to find some beefier synchros to put in there.

The speed/rev nannies can be adjusted when you get your tune.

Is it possible the clutch kit was not properly installed or adjusted and that way it would not fully disengage? But thinking of this, it should not affect the transmission but it should affect more the flywheel and shift shaft?

There are no transmission shops nearby as I live in Eastern Canada and pretty far from Montreal.

I think I might be obliged to buy another OEM transmission.

Would the dealership be able to "rebuild" my current transmission by replacing the synchros with OEM?

Rusty · 01-19-2020, 05:13 PM

Quote:

Originally Posted by NissanZ34

No I still had about 100 rpm before hitting the rev limiter which was set at 7600 rpm by the dealership. It was speed limited because the speed and rpm wouldn't budge.

Thanks for your imput.

The stock rev limit is 7,800. You can change that with Uprev or Ecutek. Why would the dealer lower the rev limit? Plus I don't think the dealer has that option with their software.

Are you talking about when the rev light flashes? If you are. You can change that yourself.

NissanZ34 · 01-19-2020, 05:22 PM

Quote:

Originally Posted by Rusty

The stock rev limit is 7,800. You can change that with Uprev or Ecutek. Why would the dealer lower the rev limit? Plus I don't think the dealer has that option with their software.

Are you talking about when the rev light flashes? If you are. You can change that yourself.

My car was rev limited at 7500 rpm when I purchased it. I asked the certified mechanic to raise it to 7600 which he did.

The certified Nissan mechanic said he can change the speed limiter, rev limiter and timing but he did not want to change the timing when I asked him to advance it.

All the modifications were installed by that mechanic.

Rusty · 01-19-2020, 05:37 PM

Quote:

Originally Posted by NissanZ34

My car was rev limited at 7500 rpm when I purchased it. I asked the certified mechanic to raise it to 7600 which he did.

The certified Nissan mechanic said he can change the speed limiter, rev limiter and timing but he did not want to change the timing when I asked him to advance it.

All the modifications were installed by that mechanic.

How did he raise the rev limit? On the dash on the right side, where the gas gauge/water temps lights are?

NissanZ34 · 01-19-2020, 06:30 PM

Quote:

Originally Posted by Rusty

How did he raise the rev limit? On the dash on the right side, where the gas gauge/water temps lights are?

With the dealership ecu management computer.

01-18-2020, 10:23 AM	#1 (permalink)
NissanZ34 Base Member Join Date: Jun 2019 Location: Canada Posts: 92 Drives: 2010 370z 6MT Rep Power: 6	Reinforcing the 6MT transmission Hello fellow Z owners. My car has about 50 000km and 4th gear is starting to show wear signs such as being clunky when shifting and not being smooth. Is there a way to bullet proof the manual transmission? I don't want to buy another OEM transmission that will fail the same way over time. It's a street car but I'm hard on it. I like speeding and found out my car was speed limited at 240 kmh in 5th gear. Would there be a way to remove the speed limit at low cost? (The dealership is a relative and probably told the mechanic to put the limiter) Modifications done so far: I already have a Stage 2 clutch kit with the lightweight flywheel from Zspeed along with their CSC delete kit. GReddy GT Evolution catback exhaust and Fast Intentions HFCs are on the way. Also have a Mishimoto oil cooler kit. K&N drop-in filters with Mishimoto silicone intake tubes. Sport and Touring package Thanks

01-18-2020, 02:16 PM	#3 (permalink)
Spooler A True Z Fanatic Join Date: Jun 2014 Location: Ga Posts: 13,834 Drives: 2013 Nismo 370z Rep Power: 2684392	Nothing really out there in the aftermarket world for our 6MT's. Just get a brand new one from Nissan and don't miss any shifts or abuse it. 2011 Nismo#91 likes this.

01-18-2020, 03:18 PM	#4 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324198	No transmission is bullet-proof - if you abuse it, you're gonna break it. The 6MT is pretty stout - some people on this site are FI'ed and running stock 6MTs with no problems. You should be able to find more than one thread on this site about beefing up the 6MT (IIRC, there's not a lot you can do) and how to use the 6MT properly. Personally, I'd get a reputable shop to rebuild the trans; might be able to find some beefier synchros to put in there. The speed/rev nannies can be adjusted when you get your tune. ZontheRocks likes this. __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

01-19-2020, 12:20 AM	#6 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 35,219 Drives: 2011 Nismo GM 6M Rep Power: 2684438	There was one member who was redoing the trannies. But he hasn't been on for a few years. The Z is speed limited to 155 mph. To remove it. You have to use UpRev, or Ecutek tuners. ZontheRocks likes this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

01-19-2020, 02:16 PM	#9 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 35,219 Drives: 2011 Nismo GM 6M Rep Power: 2684438	I'm disappointed. There's nothing about Jar in the tags. BettyZ likes this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

01-18-2020, 11:44 AM	#2 (permalink)
crazy4oldcars Enthusiast Member Join Date: Aug 2016 Location: SE Texas Posts: 448 Drives: '16 Nismo Tech Rep Power: 28413	150mph in 5th sounds about right. I think you hit the RPM limiter, not the speed limiter. Top speed is supposed to be around 165 mph (~265 kph). I have heard tales of people having their 6 speeds rebuilt with Ford synchro's, making them more durable. A search in the tech part of the forum would reveal more on that. Haven't needed the info, so I haven't researched it. From my limited reading, the rest of the transmission seems to hold up well. Kirk B.

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