# Manual Transmission Fluid Flush



## 92skirmishgti (Sep 5, 2005)

Hey guys, 

So I am going to perform a fluid change on my Corrado tomorrow, I know the CDM lakes 2.1 quarts of 75w90, now my question is whats the difference between gl-4, gl-5 and G50? 

Also any recommendation on brand and or viscosity since I live in a mostly warm climate? (socal) 

:beer:


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## bpylantvw (Jan 29, 2010)

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=498190 
This might explain better about the various oils. From what I understand gl-4 is more for lighter-duty 
applications like our cars. gl-5 and mt-1 are more for heavy duty trucks over in Europe. I bought some Total manual trans oil from www.worldimpex.com. It says that it is compatible with gl-4, gl-5, and mt-1. 
It was kinda thick though. I have research and read of people putting GM's synchromesh manual trans fluid in. Amsoil makes a 75W-90 manual trans oil. They have a product look up guide on their website, to find out if they make an oil for your trans. Hope this helped some, good luck.


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## AudiSportA4 (Mar 3, 2002)

Any Syncromesh should be fine in low power apps, under 200hp. Should be good in cold too. Syncromesh is GL-4, a Manual Trans Lube. 

GL-5 is gear oil for diffs and rears. It has friction modifiers for slipperyness that is not compatible with transmission syncronizers which need to grab and spin-up to speed. Forget about that "yellow metals" nonsense. 

GL-4 and GL-5 combo fluids are compromise fluids, not ideal at either app. Redline and AMSoil make specific separate GL-4 and GL-5 products. The Redline MT-90 is heavy 75w-90 GL-4, which is the visc used in most oldr oem applications. You can go thinner with the Redline MTL 70w-80 or 75w-85 depending on your application. Asian makes typically take 70w-80, for example. 

I just installed a mix of Redline into my 5k miles trans, equal to the 75w-85. It's thicker than the newer oem fluid that is thin like Syncromesh, it's really as thin as ATF. I have extra power, so felt the thicker fluid was more ideal. 

Let me know if you have any more specific questions.


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## bpylantvw (Jan 29, 2010)

*Thinking of changing the manual trans oil in a 08 rabbit 5spd?*

I believe that Total oil I ordered is a very thick 75W-90. If it states to conform to gl-4, gl-5, and mt-1 specs. I know Total makes good oil, but it is hard to shift when its cold, and my mpg seem to have 
gone down. Seriously considering going to Amsoils synchromesh fluid. I heard good things from other 
Rabbit owners. What brand of 75W-85 did you buy?


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## AudiSportA4 (Mar 3, 2002)

I used a Mix of Redline MTL 70w-80 and MT-90 that came out to be the same as the new MTL 75w-85, which is long proven in VAG trans at 12cSt. I have no problem with Syncromesh at 8cSt or so, that's what oem fill is now. Up to 200hp it should be safe. You can test out some $4 ATF first to see how you like the thin fluid. (MercV or Dexron VI or Mobil 1). Just sayin. 

Redline MTL 70w-80 is 10cSt, AMSoil (MTG?) has a similar product. 


lmk if you want any more info. 


http://bobistheoilguy.com/forums/ubbthreads.php?ubb=postlist&Board=16&page=1 :thumbup:


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## bpylantvw (Jan 29, 2010)

*Changing manual trans oil*

The Vw dealership at first did not want to hand over the inexpensive o-ring you require to change 
the trans oil, which the Bentley service manual says to replace. They describe it as the selector shaft journal o-ring. Guy said that the oem oil should be good for a long time or even a life time fill, and that they hadn't had any problems with the rabbit 5 spds. I still want to change it just because I can, couldn't hurt.


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## bpylantvw (Jan 29, 2010)

*Oem oil for 08 Rabbit 5 spd*

http://www.opieoils.co.uk/pdfs/New-Fuchs/TITAN-SINTOFLUID-FE-75W.pdf 
Got this from some UK site. I believe, from a lot of research, this is the oem fluid in my car. 
They call it a 75W and thats it. From the specs, it looks to be pretty thin. This oil is hard to 
find.


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## AudiSportA4 (Mar 3, 2002)

Looks good. SUPER thin at 7.6cSt. 

I used Fuchs Silkolene Pro SRG 75 Full Ester Race oil in the Astra trans. 

http://www.silkoleneoil.com/pdf/ProSRG75.pdf


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## rhouse181 (Apr 13, 2008)

AudiSportA4 said:


> I just installed a mix of Redline into my 5k miles trans, equal to the 75w-85. It's thicker than the newer oem fluid that is thin like Syncromesh, it's really as thin as ATF. I have extra power, so felt the thicker fluid was more ideal.


 How is the Red Line working out? Any problems getting into first gear when the trans is cold? 

In my M5, I tried Amsoil 75w90 and it was nearly impossible to get first and second before the trans warmed up. Refilled with Royal Purple Synchromax (cSt 7.7) and the Getrag shifted like butter at all temps... 

I want to change fluid in the Dub soon, but want to avoid any major drivability issues...


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## AudiSportA4 (Mar 3, 2002)

I have no complaints in cold. Only down to +45f so far. Thinner is the way to go. I'd use strait Redline MTL 70w-80 if I was not flashed. I heard there was a fluid addressed to quiet the 6-sp manuals. This is another reason I did not go thinner. I also had a shudder running the 93 oct programme, that is gone with the redline.


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## bpylantvw (Jan 29, 2010)

*Lubro moly "moly" gear protect?*

Have you all had any experience with lubro moly's products? I've used some of their motor oil before, and put some of that moly gear protect(looks like a thin moly grease) in the 93 honda. What are your thoughts on using in a newer Rabbit trans? I've read some bob is the oil guy threads. seems molybdenum disulfide has been used in transmissions as well as engines, but trans would benefit more.
Now tungsten disulfide is replacing moly disulfide, it is more stable and has the lowest coefficient of friction. They are using tungsten disulfide(WS2) powder in a product called "nanolube" over in Israel.
There are some articles on WS2 and their company "apnano". Nanotechnology is some interesting stuff,
especially in the automotive field, and with the improvement of lubricants.


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## AudiSportA4 (Mar 3, 2002)

ALl I can say it changing the coefficient of friction of the fluid will affect syncro engagement. IN diffs, add whatever you want.


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## bpylantvw (Jan 29, 2010)

*Kinematic viscosity?*

On the Fuchs oil I had posted before, you said it was 7.6 cSt. Did you covert 
the Kinematic viscosity? The units are metric I'm guessing. Redline's MTL 70W-80 and even amsoil's synchromesh is thicker than this Fuchs 75W oil, just comparing characteristics of all of their Kinematic viscosity. Would it be safe to run a blend of Redline's ATF that meets Gl-4 specs, or blend the 70W-80 with Redline ATF? maximizing MPG, without sacrificing reliability.


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## beastyben1 (Mar 12, 2009)

I put in Red Line MTL. Much much better than stock in the winter & getting into first. Been in there two years and seems perfect so far.


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## rhouse181 (Apr 13, 2008)

beastyben1 said:


> I put in Red Line MTL. Much much better than stock in the winter & getting into first. Been in there two years and seems perfect so far.


thanks for the feedback :beer:


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## AudiSportA4 (Mar 3, 2002)

I wouldn't go thinner than Syncromesh and would like to see GL-4 specs (which Syncromesh has). ATF is used in some trans, often Mobil 1, but it simply will not have the EP additives to deal with the heavier loading and shock placed on a manual shifter. That's my opinion. CLimate and HP levels do come into play. Let's say that if oem fluid is 7cSt, it's because it has the right additives. The Fuchs should be as good as it gets, but imo you need a GL-4 rating to go ahead.

lmk if I can help any further.

RL MTL 70w-80 at 10cSt and any Syncromesh at 8 to 9cSt would be my recommendations...generally. AMSoil has a SYncromesh product and a HD ATF. They and RL tech support can tell you exactly what is suitable, they know their product line best.


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## bpylantvw (Jan 29, 2010)

*Redline MTL mixed with MT-90...*

I went on and ordered 2 quarts of MTL, and one quart of MT-90 from amazon. Don't know if I'm going to run straight MTL or mix the two. I called Redline's tech line and they recommend MT-90, but I know thats what they are trained to do. I talked to Amsoil's tech line also, and it was the same story, he told me the Amsoil (MTG)75W-90 oil. He said synchromesh would not be good in my application. Why is the Fuchs oil look so thin on paper? Both Redline's and Amsoil's products(except for the synchromesh) are much thicker than the oem fuchs 75W oil. I guess synchromesh would break down faster than the heavier oils? or is it all about additives?


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## AudiSportA4 (Mar 3, 2002)

All gear oils shear down a bit. Syncromesh I can think of are a dino products, so all the more potential shear. I know what you're saying about having different viscs on hand to mix one way or another.

I'm surprised the RL and AMSoil techs were so conservative with their recommendations. I would think they are at least informed that the newer fluids are so thin. You have a newer Rabbit so, I assume this is the fluid you have too. 

Here is the VOA

I performed a VOA of the VW MTF which is for our 2008 Rabbit. The correct fluid is VW part number G052512A2.

Everything else is zero except the following metals:

Sn 4
Si 2
Na 1
K 40
Ca 14
P 470
Zn 8
Mo 238
B 124

VIS @ 100C 7.2
TAN 1.33

So, there you go. It's basically Syncromesh. Going slightly thicker won't hurt. I imagine RedLine MTL 70w-80 at 10cSt would be fine. I'm not trying to dictate to anyone, just throwing out the info. 66/33% mix you stated is just like mine, comes out to 11.9cSt.


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## bpylantvw (Jan 29, 2010)

*Virgin oil analysis on a synchromesh oil?*

I've never performed or had a VOA done before. I'm curious to see how the amsoil synchromesh VOA would look. Time for some more research.


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## bpylantvw (Jan 29, 2010)

*VOA of amsoil synchromesh(MTF) vs. Redline MTL*

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1647529
Interesting, both these oils are very similar to each other. What are your opinion/opinions 
on Royal Purple Synchromax? http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1541848 (RP's synchromax voa). One more thing, Redline's 
d4 atf. It provides a GL-4 rating, and is 7.5 cSt and 34.0 cst. Maybe I can use this in the 
future, but for now I'll have to be happy with the MTL/MT-90 mix.


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## AudiSportA4 (Mar 3, 2002)

It was said AMSoil formulated their MTF to copy Redline MTL.

As for Royal Purple, it's overhyped in the extreme. I don't see results with the oil any better than $2 dino oil...if not worse. See the RP gear oil thread I posted the AMSopil gear test in.

If RL claims GL-4 for D4, that would make it the ideal fluid to replace the thin oem MT lube with.


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