Manual Transmission Fluids and their viscosities

[MolaKule]

Manual Transmission Fluids (MTL) Fluids containing MTL Application Specific Additive Packages with GL-4 Ratings

Choosing a Manual Transmission fluid can be confusing.

Many times there is simply a specification referenced and no information about the viscosity of a fluid at 100C, where the oil viscosity is documented at the higher testing temperature.

What I recommend you do when looking for a replacement fluid is to determine the viscosity of the fluid at 100C either from the manufacturer's Product Data Sheet or from a New oil Analysis or VOA.

After knowing the viscosity at 100C (212F), one can then attempt to match up the fluid to one or more of those below:

A. The four MTL fluids closest to a Kinematic Viscosity of 6.1 (About the same viscosity as a DexronVI) or so are:

1. Castrol Syntrans FE 75W,

2. BMW (Pentosin) MTF-LT-3,

3. Honda MTII or MTF 2.

4. Ford FML-XT-11-QDC


B. The next higher viscosity MTL would be the 7.5 cSt versions (About the same viscosity as a DexronIII)

1. Royal Purple's Synchromax

2. Ravenol MTF-2

3. Honda MTF

4. VW part number G052512A2

5. GM Manual Transmission and Transfer Case Fluid

6. BMW (Pentosin) MTF-LT-1, 2


C. The next higher viscosity MTL would be Castrol Syntrans V FE 75W-80 8.0cSt

D. The next higher viscosity MTL would be BG Synchroshift II 8.2 cSt

E. The next higher viscosity is Mopar Type MS-9417 MTL 9.0cSt

F. The next higher viscosity MTL would be Pennzoil Synchromesh 9.3 cSt




G. The next group of MTL’s are in the 10.x cSt range are:

1. Redline MTL 70W80.

2. Amsoil MTL

3. GM Synchromeshs’

4. Volvo MTF 645

5. Ford Motor Craft XT-M5-QS


H. The next higher viscosity MTL would be:

1. Redline MT-85 – 12.0 cSt



I. The next higher viscosity MTLs would be:

1. Amsoil MTG 14.5 cSt

2. Redline MT-90 15.6 cSt

3. Castrol Syntrans Multivehicle 75W-90

 

[TallPaul]

I wonder though, if we consider Redline MTL compared to a conventional such as Valvoline ATF, the Redline MTL is considerably thicker at 100C (10.6 cSt vs 7.3 cSt), but also is considerably thinner than the Valvoline ATF at -40C (135 cSt vs 190 cSt). So the Redline MTl could actually be thinner at much of the temperature range below 100C, possibly even up to 70-80C. And if that is true, then the folks who say Redline MTL is too thick for a transmission calling for ATF don't have a solid basis for saying that.

 

[MolaKule]

I hear what you are saying TallPaul, but the purpose here is to educate those who are truly conscientious about preventative maintenance, but aren't necessarily familiar with viscosity, proper additive packages for wear prevention and synchroshift performance.

We need to get away from the confusing SAE weight designations, and think about the actual Kinematic viscosity which matches our application.

Some people still think a gear lube is a gear lube but fail to realize three major issues:

1. What is the application? MTL or Differential? The two gear lubes are NOT the same and should NOT be be used across applications
2. What is the viscosity that I really need,
3. the proper additive package. Differential gear lubes have EP additives, MTL have AW additives.

 

[Shannow]

Thanks Molakule

my Nissan wants a 75W-85 GL-4 according to Nissan, and holds 5.1L, making for a lot of oil to carry heat etc. away.

A lot of Aussies are using Mobil Agri 424 quite successfully (especially for second gear shift on a box that takes forever to warm up). I'm quite enamoured with how it runs.

http://www.mobil.com/USA-English/Lubes/PDS/GLXXENCVLMOMobilfluid_424.aspx

55cst @40, and 9.3 @ 100C...some are replacing the dexron in their autos...

I'm also using it in the Power Steering on the Caprice, as it quiets it down something major.

 

[Pablo]

Nice summary.

Originally Posted By: MolaKule
Manual Transmission Fluids (MTL) Fluids containing MTL Application Specific Additive Packages with GL-4 Ratings


G. The next group of MTL’s are in the 10.x cSt range are:


2. Amsoil MTL - Just for the record Amsoil MTF is 9.7 cSt

I. The next higher viscosity MTLs would be:

1. Amsoil MTG 14.5 cSt - Just for the record Amsoil MTG is 13.9 cSt

 

[Jim Allen]

Nice work, Mola! Thanks.

It came at just the perfect time for me as I am shopping for oils for a John Deere 3-speed combine transmission (non-hydro...it's old) and saved me a bit of legwork.

I'll put that list into my "Qwik Reference" file.

 

[rfeir]

Where does Mobil 1 Synthetic Gear Lube LS 75W-90 fit into all this as a manual transmission fluid? (2000 Audi A6 application).

 

[Wolf_Tm250]

Originally Posted By: MolaKule
Manual Transmission Fluids (MTL) Fluids containing MTL Application Specific Additive Packages with GL-4 Ratings

Choosing a Manual Transmission fluid can be confusing.



Hi,
how do you recognize the "MTL additive packages" in an oil?
Is it about the specs/approval/level ?

There are a lot of Italian Manual transmission fluids here I'd like to understand if they are really good or not...

Thanks

 

[MolaKule]

Originally Posted By: Pablo
Nice summary.

Originally Posted By: MolaKule
Manual Transmission Fluids (MTL) Fluids containing MTL Application Specific Additive Packages with GL-4 Ratings


G. The next group of MTL’s are in the 10.x cSt range are:


2. Amsoil MTL - Just for the record Amsoil MTF is 9.7 cSt

I. The next higher viscosity MTLs would be:

1. Amsoil MTG 14.5 cSt - Just for the record Amsoil MTG is 13.9 cSt




Thanks for the update.

This is about the third reported change in their viscosities; minor yet changes nevertheless.

 

[MolaKule]

Originally Posted By: rfeir
Where does Mobil 1 Synthetic Gear Lube LS 75W-90 fit into all this as a manual transmission fluid? (2000 Audi A6 application).


It doesn't, it is a differential lubricant.

Quote:
Some people still think a gear lube is a gear lube but fail to realize three major issues:

1. What is the application? MTL or Differential? The two gear lubes are NOT the same and should NOT be be used across applications
2. What is the viscosity that I really need,
3. the proper additive package. Differential gear lubes have EP additives, MTL have AW additives.

 

[MolaKule]

Originally Posted By: Wolf_Tm250
Originally Posted By: MolaKule
Manual Transmission Fluids (MTL) Fluids containing MTL Application Specific Additive Packages with GL-4 Ratings

Choosing a Manual Transmission fluid can be confusing.



Hi,
how do you recognize the "MTL additive packages" in an oil?
Is it about the specs/approval/level ?

There are a lot of Italian Manual transmission fluids here I'd like to understand if they are really good or not...

Thanks


Quote:
What I recommend you do when looking for a replacement fluid is to determine the viscosity of the fluid at 100C either from the manufacturer's Product Data Sheet or from a New oil Analysis or VOA.


The VOA can then be examined to determine the general PI package.

 

[busfreak]

looking for a replacement fluid:

temps outside now are about 0°C and in the middle of winter they will go down to -15°C.
For my car MTF 75W-85 API Gl 4 is required according to the manual.
No specific fluid (brand) is required. So I dont know the 100°C viscosity of the original factory fluid. Referring to MolaKule's listing above it will be probably between 10.0 and 12.0 cSt.
In this range the shifting effort in cold days is very very high, until the oil is warm.
I tried already RL MTL and MT85 as replacement fluid, but I'm not very happy.
My question is now, if I leave this viscosity range of MT fluids and would try Castrol Syntrans V FE 75W-80 (=8.0cSt), what would be the risk referring to

- the kind of damage
- the probability of damage ?

Castrol Syntrans V FE 75W-80 is not a ATF. It is a GL4 MTF !

thanks for answers

 

[MolaKule]

I assume you're experiencing cold weather shifting problems?

Owing to the fact of the high levels of AW in the fluids mentioned in the white paper, I don't see a high probability of failure or wear for cold weather operation.

In fact, if your gear engagement is smoother, you will most likely experience less synchro assembly wear.

Quote:
I tried already RL MTL and MT85 as replacement fluid, but I'm not very happy.


What was the perceived problem with these fluids, shiftability?

 

[y_p_w]

I remember the good 'ol days when Honda Spec'ed 10W-30 or 10W-40 motor oil for use in manual transmissions.

My only regret was that a few times I thought it might be a good idea to do back to back to back changes in quick succession. It wasn't so much that I thought it was necessary, but it with $1 quarts of motor oil and it being so easy with the right tools I figured why not when I was single and bored. Now I hear that ZDDP protection is lowest right after a fresh change.

 

[busfreak]

@molakule:

yes, I'm experiencing cold weather shifting problems. The time span from starting the car til the oil is really warm.
The problem exists only when shifting from 1st to 2nd and back.

My concern is not wear or failure in the cold.
My sorrow is that a 8.0 cSt oil is much too thin in summer with the result of wear.

The problem with MTL / MT85 is the bad shiftability in cold weather. The effort for gear change is very high. Sometimes if I shift too fast the synchro slips and a rattle is the result.

If the Castrol Syntrans V FE 75W-80 is too thin I could mix
1 quart Castrol Syntrans Multivehicle 75W-90 (11.4 cSt) with 2 quarts Castrol Syntrans V FE 75W-80 (8.0cSt) and I will get a 9.1 cSt oil. A ratio of 1:1 will end in 9.7 cSt. May be a good compromise of cold shiftability and summer viscosity.

What do you mean ?

 

[MolaKule]

busfreak, I would try the Castrol Syntrans V FE 75W-80 ( 8 cSt) until hot weather reappers and see how shifting is at that time. A 1 cSt difference in viscosity should not make much difference.

The anti-wear additives in all of these fluids should adequately protect against gear and bearing wear.

Quote:
What do you mean ?


I am not sure what this is referring to.

 

[nleksan]

How would RL D4 ATF fit? I use it for my street Bimmers, occasionally in a 3:1 ratio w MTL, but for my race cars I use the MTL due to the thicker viscosity and the extended high temp use and lack of a need for cold performance.

 

[dailydriver]

Originally Posted By: nleksan
How would RL D4 ATF fit? I use it for my street Bimmers, occasionally in a 3:1 ratio w MTL, but for my race cars I use the MTL due to the thicker viscosity and the extended high temp use and lack of a need for cold performance.


I do the same thing only for the winter (3 D4 to 1 MTL) and summer changes (100% MTL), regardless of how I am using the car.

 

[MolaKule]

Originally Posted By: nleksan
How would RL D4 ATF fit? I use it for my street Bimmers, occasionally in a 3:1 ratio w MTL, but for my race cars I use the MTL due to the thicker viscosity and the extended high temp use and lack of a need for cold performance.


Assuming your Beemer specs a 7.5 cSt fluid, I think the one of the fluids from the following list would be much better in terms of wear control:

Quote:
b]B[/b]. The next higher viscosity MTL would be the 7.5 cSt versions (About the same viscosity as a DexronIII)

1. Royal Purple's Synchromax

2. Ravenol MTF-2
[
3. Honda MTF

4. VW part number G052512A2

5. GM Manual Transmission and Transfer Case Fluid

6. BMW (Pentosin) MTF-LT-1, 2

 

[badtlc]

Don't mix the MTL. Just run straight redline MTL. I have run it in 100 degree weather down to 0 degree weather. It protects fine but gets just a tad notchy on the first shift into 2nd gear when below 30 degrees. After that first shift, it is smooth.