Oil for bronze cone syncros

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Originally Posted By: MolaKule
Quote:
We found that the bronze cone syncros are not able to slow down quick enough the gear, so the syncro get worn and you have to push harder and harder to put the gears in.


I don't understand what you mean by this statement. Is there a design problem with this MT?

See this thread for a background on MT design and lubricants:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2813713#Post2813713



Hi Molakule,
in this manual transmission, as I wrote before, there are bronze cones between syncro and gear that act as a "clutch" to match syncro & gear speed during gear engagement.
As these bronze cones are too slippery and given that gears are heavy, so with a lot of inertia, we end up having a lot of wear on syncro teeth and gear engagement that is harder and harder.
So if we want to decrease syncro teeth wear we have to decrease silpperines of the syncro cones: we found that GL5 oils are too slippery and so we get too much and too fast wear on the syncro teeth, with GL4 oils is a bit better, and we will test those NS oils
 
Originally Posted By: martinq
Originally Posted By: Wolf_Tm250
I really think, first of all, I'll try the NS Red Line oils and see what happens...

Please let us know. I don't think the 75w90 will perform as well as the MT-90 but it could be close.



Understood your point... didn't realized that NS is a "less slipping" GL5, while the MT is a GL4, so less slippery than a normal GL5...
is there a way to understand from the characteristic of these 2 oils which one is less slippery?
 
Originally Posted By: Wolf_Tm250
Understood your point... didn't realized that NS is a "less slipping" GL5, while the MT is a GL4, so less slippery than a normal GL5... is there a way to understand from the characteristic of these 2 oils which one is less slippery?

I would contact Red Line and ask them to be sure, but the MT-90 is specifically for Manual Transmissions. The 75w90NS is a synchro-friendly GL5 from the way I read it.

I've emailed Dave recently and he is an excellent assistance and really gives Red Line a good image. Try him directly:
dave (at) redlineoil [dot] com
 
Originally Posted By: Rand
usually no. but you might try it to find out for sure.

It would be hard to find a 75w140 for a transmission though.

Also I'd personally still use a gl-4 over a gl-5 less additives = better shift feel.

without hypoid gearing you dont need to worry about gl-5 vs gl-4 for protection.


GL-5 is required for extreme sliding type loads in units such as Porsche or Subaru that has a combo MT with front DIFF sharing the same oil.


Why would shift feel be better/worse [GL4-G
L5]?
It takes a dedicated manual trans lube specially friction modified to get the best synchro grab. Many are GL4 rate, but that is not the reason.
 
Originally Posted By: martinq
Originally Posted By: Wolf_Tm250
Understood your point... didn't realized that NS is a "less slipping" GL5, while the MT is a GL4, so less slippery than a normal GL5... is there a way to understand from the characteristic of these 2 oils which one is less slippery?

I would contact Red Line and ask them to be sure, but the MT-90 is specifically for Manual Transmissions. The 75w90NS is a synchro-friendly GL5 from the way I read it.

I've emailed Dave recently and he is an excellent assistance and really gives Red Line a good image. Try him directly:
dave (at) redlineoil [dot] com


Perfect, thanks!
smile.gif
 
Originally Posted By: wannafbody
Amsoil MTG is a good fluid for this application.


Already bought the Redline... if I will still need to test another oil, I'll try this one, thanks
 
GL-5 oils because of their higher antwear tend to be corrosive to Cooper and bronze. GL-4 with it's lower antiwear tend to be less corrosive. Balance is between gear wear and copper corrosion.
A lot of the newer dual clutch transmissions (DCT) have the same balance problems. Using an oil recommended for DCT might help.
 
I will be interesting to see if the NS actually does what you need. I constantly have to remind people and insist that a normal GL-5 will wear the synchros.

Besides the GL-4, I've had good luck in Toyota race cars with TO-4 SAE 50 (CAT spec). Designed for the wet brakes and clutch packs on CAT & Komatsu equipment.
 
This thread amazes me in that I dont think people really understand the requirements for a gearbox lube.In my experience a GL5 oil is designed for differential use only and if used in a manual gearbox leads to poor shift quality and actually more wear than a purpose made synchromesh oil.The other point is there seems to be a trend for synchro oils to become thinner in a desire to improve the shift quality.There has not been an increase in gearbox wear as a result that I am aware of.For instance the Mazda MX5 and Honda S2000 share the same Aisin gearbox,Mazda spec 75w90 and Honda MTF,I bet you the Honda has the better shift feel and both gearboxs have a similar life span.An interesting observation I have made is that the 3 synchro oils I have used do not have the usual sulphur smell of a standard GL4/5 oil.The heavy truck industry has used engine oils in their transmissions for years,I can vaguely remember attending a seminar run by the local Fuller Roadranger company where they warned us not to use gearlubes in their trans and only 50 weight engine oils.The explanation was the engine oils made their trans last longer,so much for so called gear oils.So to conclude,what should they use in their gearbox,my recommendation is a dedicated synchro oil;ie RedlineMT90,MTL,Amsoil MTG,MTF or if not avaiible in Greece a 10w30 or 15w40 synthetic engine oil.By the way those Aisin gearboxs in your Toyota are tough as,any oil will keep the gears well lubed.
 
Originally Posted By: widman

Besides the GL-4, I've had good luck in Toyota race cars with TO-4 SAE 50 (CAT spec). Designed for the wet brakes and clutch packs on CAT & Komatsu equipment.


Thanks for the input
 
Originally Posted By: JimmyChainsaw
This thread amazes me in that I dont think people really understand the requirements for a gearbox lube.In my experience a GL5 oil is designed for differential use only and if used in a manual gearbox leads to poor shift quality and actually more wear than a purpose made synchromesh oil.



Definitely


Quote:

The other point is there seems to be a trend for synchro oils to become thinner in a desire to improve the shift quality.There has not been an increase in gearbox wear as a result that I am aware of.For instance the Mazda MX5 and Honda S2000 share the same Aisin gearbox,Mazda spec 75w90 and Honda MTF,I bet you the Honda has the better shift feel and both gearboxs have a similar life span.An interesting observation I have made is that the 3 synchro oils I have used do not have the usual sulphur smell of a standard GL4/5 oil.The heavy truck industry has used engine oils in their transmissions for years,I can vaguely remember attending a seminar run by the local Fuller Roadranger company where they warned us not to use gearlubes in their trans and only 50 weight engine oils.The explanation was the engine oils made their trans last longer,so much for so called gear oils.



Thanks for the info!



Quote:

So to conclude,what should they use in their gearbox,my recommendation is a dedicated synchro oil;ie RedlineMT90,MTL,Amsoil MTG,MTF or if not avaiible in Greece a 10w30 or 15w40 synthetic engine oil.


In Italy I can pretty get Redline or make someone to ship me the Amsoil...
anyway we have here a big petrol company, Eni/Agip, that makes a loooooong list of oils for engine and transmission, and I bet I could even find here a good oil for our synchros...
if only i could understand which characteristics to look for that indicates an oil that will help more the syncros to slow down, that is to say less wear.
For sure it has not to be a GL5!

Here is the list, in English:

http://travel.eni.com/iveportal/products...p;x=52&y=11
 
Originally Posted By: DWC28
GL-5 oils because of their higher antwear tend to be corrosive to Cooper and bronze. GL-4 with it's lower antiwear tend to be less corrosive. Balance is between gear wear and copper corrosion.
A lot of the newer dual clutch transmissions (DCT) have the same balance problems. Using an oil recommended for DCT might help.


Thanks
 
Originally Posted By: DWC28
GL-5 oils because of their higher antwear tend to be corrosive to Cooper and bronze. GL-4 with it's lower antiwear tend to be less corrosive.

Both GL4/5 oils can be corrosive to brass if they contain added sulfur but GL5 allows for a higher amount. Some oils like the Motul Gear 300 do not use the sulfur/phosphor additive but still provide protection above GL5 so they can be labeled as GL4 & GL5.

This is a nice read on GL4 vs GL5.
http://www.widman.biz/uploads/Transaxle_oil.pdf
http://www.widman.biz/Corvair/English/Links/Transaxle.html

PS, thanks for all the great info widman!
 
Last edited:
Originally Posted By: martinq
Some oils like the Motul Gear 300 do not use the sulfur/phosphor additive but still provide protection above GL5 so they can be labeled as GL4 & GL5.


I REALLY wish that Motul made the ultra-high VI Gear 300 in a 75W-140/> 27.0 cSt @100* C viscosity!!
frown.gif
 
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