Synchromesh Manual Transmission Lubricants

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Originally Posted By: Kamele0N
Do you use generic 20w50 API SN or JASO MA API SG?


Mine has had Wal-Mart Supertech 20W-50 since I put the current transmission in it a year and a half ago. I think it's just a plain old API SN.

Thanks for confirming MT-90. Since I'm planning on putting an O/D trans in it within the next year, I'll leave the generic 20W-50 for now and save the $60 worth of MT-90 for the OD.
 
Originally Posted By: MolaKule
For the Laycock de normanville overdrivesystem and tranny I would stick with something like MTL-75W85 or MT-90.


The reason for the old 20W50 spec was the then current mineral oil would shear down in viscosity under heat.



Thank you
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I guess the Pennzoil Syncromesh may be lower viscosity than is ideal, but it was the only MTL available locally 20 years ago. However it has worked well in so far as the transmission changes nicely, and the O/D engages with authority.

I wonder if EP additives such as Moly in a 20w-50 engine oil could have a more serious derogatory effect on syncros or the wet clutch?
 
Originally Posted By: expat


I wonder if EP additives such as Moly in a 20w-50 engine oil could have a more serious derogatory effect on syncros or the wet clutch?


The amount of Moly contained in MO's is acting as a friction modifier.

Any other type of friction modifier in a MT can very well affect and interfere with the specific friction modifier chemistry used in current MTFs'.
 
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Is this still the case? GM Synchromesh 'better' MTF than Pennzoil Synchromesh? Appears to be some confusion and discussion as to whether they are identical products. Thanks in advance.
 
I will give you some technical information and you can form your own opinion:

Formulations can change without notice and suppliers can change without notice but here is my latest info:


Pennzoil Synchromesh has an average viscosity of ~ 9.5 cST@100C and has a predominately mineral oil base with a good Friction Modifier.


GM Synchromeshs' have an average viscosity of ~ 10.5 cST@100C and are Blends of Synthetic and Mineral Oils with a good Friction Modifier.
 
MolaKule, Thanks for valuable information.
If you don't mind i want to ask off-topic question.
Can you please tell me, Do we need high or low friction between gear and the blocker ring for smoother shifting ?
As far as i know, if the friction high, blocker ring can easily synchronize the speed. But in this case doesn't more friction mean more wear ?
Regards.
 
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Can you please tell me, Do we need high or low friction between gear and the blocker ring for smoother shifting ?
As far as i know, if the friction high, blocker ring can easily synchronize the speed. But in this case doesn't more friction mean more wear ?



The specific friction modifier allows for a changing friction coefficient called the, "dynamic friction coefficient."

What you want to happen (whether it be MT clutches or in wet clutches as in Slip-Shift clutches in ATs) is to have the friction coefficient change with both the applied forces encountered and the relative speeds of the components for a smooth transition.

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Coefficients of Friction
However, there are two coefficients:

i) The limiting coefficient of static friction. This is based on the force required to start the body moving.
ii) The dynamic coefficient of friction. This is based on the force required to keep the body moving at constant velocity across the surface.


http://www.slipalert.com/friction/
 
Nice to see you again Molakule. You were missed. Was kind of a lion void for the past month or so.
 
Originally Posted By: 3xSHO
Is this still the case? GM Synchromesh 'better' MTF than Pennzoil Synchromesh? Appears to be some confusion and discussion as to whether they are identical products. Thanks in advance.


I have mentioned in other posts/threads that the GM synchromeshes are part-synthetic blends while the Pennzoil Synchromesh is predominately mineral oil based, so the GM synchromeshes should offer better cold weather shifting properties.
 
I thought I saw in some other thread you're cool with using gl5 oils on trans with brass synchros as corrosion/tarnish issues are minimal. All the brouhaha about needing gl4 is overblown. As long as it shifts acceptability with gl5 lube.

Redline now recommends their 75w90 gl5 instead of the mt90 gl4 for Borg warner st10 and muncies
 
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As long as it shifts acceptability with gl5 lube.


And there is the rub. GL-5 rated differential oils do not contain the friction modifiers needed for smooth shifting in most synchronized car and light duty transmissions.

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Redline now recommends their 75w90 gl5 instead of the mt90 gl4 for Borg warner st10 and muncies


Redline also thinks their D4 ATF qualifies as a GL-4 rated gear lubricant.

I could see them recommending their shockproof oils since these oils contain a component very similar to the friction modifier in dedicated GL-4 MTF fluids.


Do you have a link which documents their change of mind?
 
Originally Posted By: Shannow
Does that fall under your statement that all salesmen lie ?



For sure.

So has Redline discovered their MT-90 can't provide enough wear protection to handle Muscle Car transmission torques, so they are now recommending a GL-5 gear lube? I think it is a mistake to embark on a "Peanut-Buttering" approach to gear lube coverage.

Why not formulate for a new MT-90 version and call the new product something like MT-90MCMTF or such like?
 
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Lion?

I was thinking more like the professor on Gilligan's Island.

So I'm thinking of making some special sauce. Straight 250w gear oil with the lubro moly additive.

That nulon ptfe stuff shannow showed me looks interesting too. Can't get it here. It'll cost more than its worth for him to ship it to me

1040.jpg
 
Originally Posted By: MolaKule
Originally Posted By: 3xSHO
Is this still the case? GM Synchromesh 'better' MTF than Pennzoil Synchromesh? Appears to be some confusion and discussion as to whether they are identical products. Thanks in advance.


I have mentioned in other posts/threads that the GM synchromeshes are part-synthetic blends while the Pennzoil Synchromesh is predominately mineral oil based, so the GM synchromeshes should offer better cold weather shifting properties.


Make sure to get the GM Syncromesh "Friction Modified" version. It is what we use at Honda for slow syncros.
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I am currently doing a borg warner T5 swap in my nova due to transmission and column problems. I bought three quarts of pennzoil synchromesh to go in the transmission.
 
Manual Transmission (MT) Lubricants (Updated 6/26/2019)
By MolaKule


Ever since dedicated MT fluids appeared on the scene (such as the GM Synchromesh series of fluid), drivers have seen better shifting due to better synchro engagement and improved shifter-fork movement, attributed to the specialized additive package used in these lubes. Before these fluids were introduced, engine oil's such as 5W30 or gear lubes such as 75W90's were specified, depending on design.

Note: This white paper is directed toward light truck and passenger vehicle manual transmissions. We will not be discussing transmission lubricants for Heavy Duty truck transmissions or those transmissions requiring MT-1 rated lubricants.

One of the first of these dedicated MT fluids were the GM Synchromesh series of fluids in the viscosity range of API 5W30 engine oils, or the SAE Gear Oil 80W85 range, or 10.5 cSt@100C. These fluids were originally targeted for the GM series of synchromesh transmissions. Purported to have been formulated by Texaco, these early MT dedicated GM fluids were partial synthetic fluids that contained a synthetic oil component of alkylated benzene for low temperature operation. The AW component was primarily a reduced level of EP additives with a low level treatment of ZDDP for anti-oxidant purposes. Later, the EP additive was dropped for increased levels of ZDDP as the primary AW additive. Today's MT fluids contain a multi-functional phosphorus chemistry as the primary AW additive with increased levels of synthetic fluids.

Then along came Pennzoil which introduced "Pennzoil Synchromesh" MTF with a 9.3 cSt@100C viscosity. This fluid fulfilled the specifications for both GM and Chrysler manual transmissions as their factory fill. Later, companies such as Amsoil and Redline introduced MTF's in various viscosities.

These fluids were successful because they introduced a specific friction modifier chemistry that insured smooth synchro engagement and disengagement.

Dedicated or Application Specific MTF's for Manual Transmission or Transaxle use an additive package containing Anti-Wear (AW) additives, rust and corrosion inhibitors, emulsifiers, and specialized Friction Modifiers, and are generally protection rated at the SAE GL-4 level.

Now GL-4 does not necessarily refer to MTF's, as there are some gear lubes in the
Market place that are GL-4 rated, but are not MTF's. GL-4 is an SAE wear protection rating.

There are a few MT fluids GL-5 rated for specific vehicles that have common MT and Differential sumps. One such manufacture, Subaru, has transmissions which shares a common sump and require a MTF which is GL-5 rated.


Manual Transmission fluids use a different Friction Modifier for synchro engagement,
a modifier that is NOT the same Friction Modifier chemistry as used in differential lubes,
engine oils, or hydraulic fluids.

Here, Friction Modifier or Friction Modification does NOT refer to friction reduction.
Here, Friction Modifier refers to a chemical compound that gives rise to a situation
such that the coefficient of friction (COF) varies Dynamically with respect to the
relative speed of parts that mesh and de-mesh during engagement and disengagement of rotating parts.

(For a similar discussion of ATF's and friction modification, please see: https://bobistheoilguy.com/forums/u...TF_and_Friction_Modification#Post1111352 ).


When selecting a replacement fluid for a manual transmission or transaxle, one has to consider the viscosity of the fluid for which the manual transmission or Transaxle was designed. The spectrum of viscosities for light truck and passenger vehicle transmissions now range from 6.0 cSt@100C to 75W90 viscosities and therefore a dedicated MTF can be any viscosity from 6.0 cSt with an approximate SAE 70-75W80 grade ( a viscosity or grade similar to ATF's) to an equivalent SAE 75W90 grade viscosity of approx. 14.5 cSt@100C.

For example, if your transmission requires a 14.5cST@100C fluid, an SAE 75W90 fluid should be used. In some cases, a 75W85 synthetic fluid has been shown to provide better cold weather shifting, while still providing sufficient anti-wear protection and fluid film thickness. In many cases, one has to experiment with fluids of slightly different viscosities to determine which fluid works best in your local climate and specific transmission.

We should also mention that transmission wear can also require a change in viscosity as well. However, no OTC additive or change in viscosity will cure a transmission that has severe wear in its bearings, gear teeth, or synchronizer assemblies.

It is recommended that an examination of clutch engagement and a change in transmission fluid be done before rebuilding a transmission. For the latter, crunching and "notchyness" can be caused by the old fluid having been sheared (loss of viscosity) and the degradation of its additive chemistry.

Many MT manufacturers have introduced fluid specifications for fluids with lower viscosities in the range of 6.0cSt@100C to 7.5cSt@100C, a viscosity in the same range as ATF fluids. These fluids were specified primarily to increase fuel mileage in order to raise fleet fuel mileage figures.

Some fluid manufactures' such as Royal Purple and the fluid supplier for GM, have developed MTF fluids in this viscosity range. These fluids are basically ATF fluids with a bump in the AW components.

One manufacturer, Tremec for example, currently specifies Dexron III/Mercon ATF fluids. It is the opinion of this author that the design of this transmission can only use ATF because of cold temperature operation problems. In earlier specifications, they specified higher viscosity MTF's, while in the latest specification, they specify ATF's, yet the internals are supposedly the same. My guess is they found that, with their original specs for the higher viscosity fluids, shifting was poor in cold weather, so they dropped the viscosity and at that point in time, the only available fluid with a low viscosity was ATF - which is no longer the case. Now there are new low viscosity fluids on the market with improved additive packages. In terms of the composite materials used in the ring-blocker assembly of these transmissions, the friction modifiers in ATF's do nothing for synchronizer operation. The shearing of the fluid at the interface is the primary means of dynamic friction modification.

Current MTF's in the range of 8 cSt to 10 cSt, designed for metal-alloy synchronizer assemblies, have been shown to work in these same transmissions without blocker-ring degradation or excessive wear.

One last comment: MTF specific lubes were developed for manual transmissions and transaxles, and not for differentials or industrial gear boxes, and vice versa. A differential lubricant is not a good choice for MT's. A dedicated differential fluid of 75W90 with a GL5 rating usually has a higher viscosity than does an MTF in the same advertised grade, and will therefore cause shifting problems in cold weather. In addition, a differential lube does not contain the proper additive package needed for MTF's, since it contains an Extreme Pressure additive package meant for highly loaded hypoid gearing.

In summary:

1. GL-5 and MT1 rated gear lubes have a higher viscosity than MTF's of the same SAE Gear Oil viscosity range,

2. GL-5 and MT1 rated gear lubes have a different additive package than do MTF's; MTF's contain Anti-Wear additives, GL-5 and MT1 rated gear lubes contain Extreme Pressure (EP) chemistry.

3. GL-5 and MT1 rated gear lubes have a different additive package than do MTF's; MTF's contain specialized Friction Modification chemistry; GL-5 and MT1 rated gear lubes containing LS additives have special Friction Modification chemistry that is different than what is found in MTF's.


Here is an updated list of dedicated GL-4 and a few GL-5 MTL's.

Much confusion over the viscosities (thickness) of MTF fluids is the result of the SAE gear oil charts and its ranges seen at:

https://bobistheoilguy.com/viscosity-charts/


NOTE: This list is only a "suggested" list of MTFs. It is not an endorsement of any one fluid, nor is it implied that any one fluid will cure problems in MTs that have design problems or those that have excessive wear.

A. These MTL fluids are closest to a Kinematic Viscosity of 6.X cSt@100C (About the same viscosity as a Dexron VI) and SAE 70 or so:

1. Castrol Syntrans FE 75W,
2. BMW (Pentosin) MTF-LT-3,
3. Honda MTII or MTF 2.
4. Ford FML-XT-11-QDC
5. Volvo Manual Transmission Fluid (6.4 cSt) [Recommended for: type M65 5-speed with 6-cyl. engine, M66, MTX75 and MMT6 and of the type M56, M58 and M59 from and including model year 1996. Meets Ford specification WSSM2C200-D2]
6. Redline MT-LV SAE Viscosity Grade 70W/75W Vis 6.5cst@100°C


B. The next higher viscosity MTL would be the 7.0 to 7.6 cSt@100C versions (SAE 70W75) (About the same viscosity as the original DexronIII/Merc)

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 2) MTF-LT-1, 2 ,3
7. Tutelo (Petronus, Italy, Product Code 1402)
8. Pentosin Pro Gear 70W75 (Australia)
9.0 Pentosin FFL-4
10. Redline Power Steering Fluid
11. RAVENOL STF

C. The next higher viscosity MTL group is in the 8.0 cSt to 8.9 cSt Range would be:

1. Castrol Syntrans V FE (8.0cSt)
2. Redline DCTF Dual Clutch Transmission Fluid (8.1 cSt)
3. BG Synchroshift II (8.2 cSt)
4. RAVENOL PSA

Note: C, D and E are often considered popularly as "synchromesh" fluids, even though this description is not entirely correct.


D. The next higher viscosity MTL group in the 9.0 to 9.5 cSt range is (SAE 75W80):

1. Mopar Type MS-9417 MTL 9.0 cSt
2. Valvoline MTF Part Number 811095 9.2 cSt
3. Pennzoil Synchromesh 9.3 cSt
4. RAVENOL PSA 9.5 cSt
5. RAVENOL SSG 9.5 cSt


E. The next group of MTL's are in the 9.6 to 10.X cSt range (SAE 75W80):

1. Redline MTL 75W80
2. Amsoil MTF (9.7 cSt)
3. GM Synchromesh's
4. Volvo MTF 645
5. Fuchs TITAN SINTOFLUID SAE 75W-80 synthetic MTF
6. Lodexol (Morris Lubricants) MTF
7. Motylgear 75W-80


F. The next higher viscosity MTL would be a 12.0cSt@100C and SAE 75W85:

1. Redline MT-85


G. The next higher viscosity MTLs in the 14-15 cSt (SAE 75W90) range would be:

1. Amsoil MTG
2. Redline MT-90
3. Castrol Syntrans Multivehicle 75W-90
4. Castrol Syntrans Transaxle 75w-90
5. Ford XT-75W90-QGT
6. Ford MOTORCRAFT® Full Synthetic Manual Transmission Fluid XT-M5-QS
7. ACDelco 10-4059 GL-4 75W-90 Manual Transmission Fluid
8. RAVENOL TSG SAE 75W-90
9. LiquiMoly 75W-90 GL4
 
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