How to change manual transmission fluid

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murcod
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Joined: Fri Aug 03, 2012 12:03 pm
Location: Australia

avluis wrote:
murcod wrote:
avluis wrote: Redline does this car justice.
Will you guys stop it! I don't want to void my warranty. :D

Another option is Redline 75W90NS which is GL5 rated but friendly to synchros (unlike most GL5 oils.) I used it in my last vehicle. The higher GL5 rating should give better protection.
I considered that one as well, but did not want to fall out of recommended specs with any of the recommended oil weights. Will consider in the future if someone else does it :P
The weight is within spec (75W90)- it is listed in that factory manual you're hosting. There's a bit on GL4 and GL5 here: http://en.wikipedia.org/wiki/Gear_oil http://wiki.answers.com/Q/Whats_the_dif ... _gear_oils
David
bootymac
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Joined: Fri Jul 19, 2013 1:04 am

I'm a bit weary of using GL5 when it's not specified by the manufacturer. I've heard that it can cause some serious problems with synchros. Apparently it can damage brass and other yellow metals and the friction modifiers actually prevent synchros from functioning properly, resulting in difficulty shifting
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KuroNekko
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Location: California, USA

bootymac wrote:I'm a bit weary of using GL5 when it's not specified by the manufacturer. I've heard that it can cause some serious problems with synchros. Apparently it can damage brass and other yellow metals and the friction modifiers actually prevent synchros from functioning properly, resulting in difficulty shifting
Yeah, I stuck with GL-4 lube for that reason. While I am sure that new formulas would be safe, it's best to stick with tried and true lubes until things are determined.
The great thing about Red Line lubes like MTL and MT-90 is that they were specifically made for manual transmissions. In fact, I believe "MT" in MTL and MT-90 stands for Manual Transmission.
My guess is that MTL stands for Manual Transmission Lubricant and MT-90 stands for Manual Transmission-90 weight.
2011 Suzuki Kizashi Sport GTS 6MT (Black)
murcod
Posts: 2279
Joined: Fri Aug 03, 2012 12:03 pm
Location: Australia

bootymac wrote:I'm a bit weary of using GL5 when it's not specified by the manufacturer. I've heard that it can cause some serious problems with synchros. Apparently it can damage brass and other yellow metals and the friction modifiers actually prevent synchros from functioning properly, resulting in difficulty shifting
Yes, that's the whole point about the Redline 75W90NS - it's one of the few GL5 specified lubricants which (going by Redline's own literature) isn't corrosive to brass synchros and can be used in manual transmissions. From what I understand (generically speaking about GL4 and GL5 lubricants) GL5 lubricants use high levels of sulfur-phosphorous additives and that preclude them from being synchro friendly; GL4 lubricants still contain these additives, but at lower concentrations.

So, in theory with the 75W90NS you get the extreme pressure protection of the GL5 without the corrosion to the synchros.

It's even listed of the Redline site under http://www.redlineoil.com/Products.aspx?pcid=7 " RED LINE GEAR OIL FOR MANUAL TRANSMISSIONS ".
CORROSION PROTECTION
The extreme pressure chemistry used in many gear oils
can be corrosive to brass and bronze used in synchronizers
and bushings. Most gear oils are corrosive at
temperatures of 200°F. Red Line Gear Oils are non-corrosive
up to 300°F and the MTL® in excess of 375°F. A
corrosive gear oil can shorten synchronizer life by half
and can also contribute to rust problems.
from http://www.redlineoil.com/content/files ... 20Info.pdf
DIRECTIONS FOR USE
Red Line MTL may be used in transmissions which
recommend 75W, 80W, or 85W GL-4 gear oils, or SAE
30 or 5W/10W30 motor oils. If a 90W GL-4 or SAE 40,
10W40, or 15W40 is required, MT-90 may be used. If the
transmission or transaxle requires an SAE 90 GL-5 gear
oil, then Red Line 75W90NS or 75W140NS Gear Oil
may be used.
from http://www.redlineoil.com/content/files ... 20Info.pdf

It's another option that should provide even superior protection against wear. It probably would be a good thing in a turbo conversion. ;)

http://forum.miata.net/vb/showthread.php?t=213915
There are two threads going here on Redline gear oils, and one is my results using it. There was some concern that the 75w-90NS being a GL-5 Gear Oil would cause damage to the Snychros in the Miata Tranny. Below is my e-mail to Redline, and their reply. I thought best to start this new thread, to answer the other two threads.

My E-mail:
After reading on your web page about your "75w-90 NS" gear oil, I just put 2 quarts of it into the 5 speed transmission in my 2002 Mazda Miata. I read where it was supposed to let the snychros work better, for smoother shifts. The transmission seems to shift very smoothly, and so far I am happy with this.

BUT....

I have been reading some posts on the Miata.Net web page, and I read where this "NS" oil will reduce the snychronizer life by about 1/2, and it is not good for a Mazda Miata manual transmission.

Also, someone is trying to say the NS means "Low Sulphur". Is this correct, or what does the "NS" stand for?

Will you please comment to me on this? I am VERY concerned that I may have put the wrong gear lube in my Miata 5 spd Transmission!?!?!?

Thank you


REPLY FROM REDLINE:

Bill,

Thank you for contacting Red Line Oil, glad the 75W90NS is performing well in your Miata transmission.
Neither the 75W90NS nor any of our GL-5 gear oils are harmful to brass or bronze synchros, they are not corrosive and do not cause pitting or metal removal. Some GL-5 gear lubes do contain sufficient EP additives to be corrosive, those could consequently reduce synchro life by 50%. The "NS" refers to No Slippery additives, it has essentially no friction modifiers so it isn't too slippery for the synchros in a manual transmission. There is no need for concern using the 75W90NS in your transmission.


Regards, Dave
Red Line Oil
David
bootymac
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Joined: Fri Jul 19, 2013 1:04 am

Good to know! Thanks for sharing
murcod
Posts: 2279
Joined: Fri Aug 03, 2012 12:03 pm
Location: Australia

I think I mentioned earlier that I used it in my last vehicle's manual transmission (with brass synchros). I didn't have any problems, but it sounds like you'd need to own a vehicle for a very long time before you did (a lot of articles mention halving the synchro life with normal GL5 lubricants.)
David
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Soviet
Posts: 35
Joined: Thu May 02, 2013 5:32 am
Location: Oklahoma

thanks!!!!
uzz32
Posts: 13
Joined: Sat Apr 07, 2012 1:28 am

Just dropping in to thank Kuronekko for posting this tutorial. I used it as a guide to perform my own transmission oil change and she shifts much better. The oil change has minimised my second gear transmission rubbing noise.

I did not go the 75w90 route because Redline oils are expensive in Australia ($27 bottle). I used Castrol 75w85 mineral oil as I figured that anything would be better than the factory oil, which had done 40,000 km.
uzz32
Posts: 13
Joined: Sat Apr 07, 2012 1:28 am

Furthermore, I also flushed my clutch and feel this has made a difference. The clutch as has much more retardation, which seems to facilitate for quicker shifting. I can post a short tutorial with a couple of pictures if anyone is interested.
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KuroNekko
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Joined: Wed Aug 15, 2012 5:08 pm
Location: California, USA

uzz32 wrote:Furthermore, I also flushed my clutch and feel this has made a difference. The clutch as has much more retardation, which seems to facilitate for quicker shifting. I can post a short tutorial with a couple of pictures if anyone is interested.
Yes, please do. I have never heard of a clutch flush.
2011 Suzuki Kizashi Sport GTS 6MT (Black)
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