Synchromesh Manual Transmission Lubricants

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Me too, I prefer the older chevy Burbs with the gas piston in the front diffy and the gearshifting TC, but these AUTO 4 Wheel drive Transfer cases (as in my '08 TrailBlazer) are really nice on icy and snowy roads.

I recommend changing the TC fluid after a tough winter.
 
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What issues with RP Syncromax in manual transmissions? I'm not a fan of the brand, but I figure it's gotta be better than ATF in those units that spec ATFs and no one makes a comparable fluid that I know of.

Mola, you don't recommend RP Syncromax for manual transmissions and transfer cases that spec ATFs? Please PM me if you think your answer will start trouble.
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No problem. It's that I have never had any experience with it nor run comparisons against other lubes.
 
Hmmmmmm. The kid just changed the lube in the manual tranmission in his '01 Miata due to a torn boot and some amount of leakage...... M1 75W-90 "LS".

He claims that it doesn't shift nearly as well as it once did.....

Now we know why.

Thanks

Is this a great forum or what ???
 
From what I understand some 6-speeds have paper (cellulose) syncros and most synthetic oils do not work with the paper very well. (It may eat them up) I can't recall what years and such have the paper syncros but in my 2000 z-28 6-speed (paper syncros from what I could find out? YMMV) I put pennzoil dex-III (dino) in it and what I drained out (FF) sure looked like dex-III to me.
 
There was a thread on Stangnet that went for tons of pages. It's still there to read. There were problems with the 1-2 shift in the TR3650's. After a good while some Tremec engineers finally came in and gave some info.

Apparently the GM SynchroMESH is not good for the Tremec trannies. However they said that SynchroMAX was ok to use. They also said to drop the capacity from 3.9 qt. to 3.2. This is some stuff that Ford really never bothered to tell anyone.

I believe the same MESH vs MAX difference also applies to the T56.
 
how about mixing 50/50 ATF and MTL for a manual trans that specs ATF4? it would make a slightly thicker viscosity and also add in some EP additives. I will try to get ahold of Dave at RL to see what he says about mixing their different fluids...
 
GL-4 is a level of protection rating for gears and is generally applied to manual transmissions and to manual transaxles that do not have hypoid designs.

The older formulations in GL-4 MT lubes had about 1200 to 1500 ppm of phosphorous and zinc or ZDDP as the primary Anti-Wear additive. Some simply contained a lower level of phosphorous-sulfur EP additives like those used in differential (GL-5) lubes.

GL-4 MT lubes don't need a strong EP additive level like the phosphorous-sulfur EP levels in a differential lubricant because of the type of gearing and gear-tooth loading.

If you care to read the White Papers you will see that gear lubes, whether GL-4 or GL-5, have more than just Anti-Wear (AW) or Extreme-Pressure (EP) additives.

ALL Gear lubes contain anti-rust, anti-foam, and Metal Deactivator chemistries.

Metal Deactivator chemistries are chemical compounds that keep an additive component or contaminant from reacting with metals in the gear box.

The important thing to keep in mind about the Specific Application GL-4 MT lubes is that they contain the proper friction modifier chemistries to assist with better shifting and synchro engagement.

Personally, I relegate GL-5 rated lubes to hypoid differentials only.
 
Used by Permission of the Author for BITOG

Protection-wise, most Manual Transmisson Lubes are rated with an API protection rating of GL-4 because of the type of gearing used as will be explained later.

I think manual (or Stickshift or Standard) transmissions are more fun to drive than automatic transmissions. Manual transmissions require more driver interaction than do automatic transmissions. You can’t talk on the cellphone, or eat, or text when you have to shift gears.

In this paper we examine the internal mechanisms of the manual transmission and the effects of the lubricant’s viscosity and additives. We are discussing light truck and passenger vehicle manual transmissions only. We will not discuss OTR or heavy-duty transmissions which use a different type of lubricant.

A modern gearbox is of the constant mesh type, in which all gears are always in mesh. The exception is the reverse idler gear which will be explained later. This constant mesh and the cut of the gears insure a rather quiet transmission. In any one gear, only one of these meshed pairs of gears is locked to the shaft on which it is mounted. The others are being allowed to rotate freely; thus greatly reducing the skill required to shift gears. Most modern cars are fitted with a synchronized gear box, although it is entirely possible to construct a constant mesh gearbox without synchromesh, as found in motorcycles for example.

Some manual transmissions are integrated with differentials to form a “Transaxle.” The differentials here are usually NOT the hypoid types found in larger vehicles, but are of the spider gear configuration.

Going from the top of the transmission case downward, we have the shifter mound which contains the shift lever and linkages. The shifter will have a seal or boot at the top with an additional gasket to keep the lubricant from flowing out when slung by the gearing. Below that are two shafts, one the input shaft and the other being the output shaft. The input shaft is splined to the clutch for power connect or disconnect. The output shaft goes to a universal joint, then to the driveshaft (a hollow “torque” tube), and the driveshaft connects to the differential via another universal joint.

An illustration of a basic manual transmission is found here, so exercise the shifting as we discuss the mechanisms (not a perfect illustration but makes the point):

http://auto.howstuffworks.com/transmission4.htm

Shifter Assembly: The gears resting on the top shaft, the input shaft, are locked onto that shaft and rotate at the same rpm as the engine. The bottom output shaft has synchronizers “splined” to this shaft, so they can move around as the gear ratio is changed. The gears on the output (bottom) shaft are allowed to rotate freely on the output shaft or on small roller or “needle” bearings, depending on the horsepower transmitted and the design. The output shaft will rotate at various rpms depending on gear selection. In first gear, for example, you want low output shaft rpm and high torque.

The shifter moves the associated linkage which connects to the shifter forks. The linkages position the shifter forks, and effectively “programs” the shifter forks in order to select the required gear ratio. I.E., for each shift lever position, the shifter forks are moved around to drive the splined synchronizers on the output shaft. The shifter forks have a bore so they can slide on the guide rods. There is a specified clearance between the shifter forks’ bore and the shifter fork guide rods. Lubricant effects: Too high a viscosity lubricant and the shifting will be hard and sluggish. More force will be required to go from one gear to another. Too thin an oil and the forks will wear, the clearances will increase, and the shifting will become sloppy and uncertain. The correct mix of base oil viscosities is needed here to insure good cold weather and hot weather shifting. Synthetics excel here because of their high viscosity index.

Synchronizer: The locking mechanism for any individual gear consists of a collar on the shaft which is able to slide sideways so that teeth or “dogs” on its inner surface bridge two circular rings with teeth on their outer circumference; one attached to the gear, one to the shaft. (One collar typically serves for two gears; sliding in one direction selects one transmission speed, in the other direction selects the other) In our illustration from above, the bottom or output shaft has splines that mate with the synchronizer “collar.” The synchronizer collar moves transversely on the splines, positioned by the shifter fork. When the rings are bridged by the collar, that particular gear is rotationally locked to the shaft and determines the output speed of the transmission. In a synchromesh gearbox, to correctly match the speed of the gear to that of the shaft as the gear is engaged, the collar initially applies a force to a cone-shaped brass clutch which is attached to the gear, which brings the speeds to match prior to the collar locking into place. The collar is prevented from bridging the locking rings when the speeds are mismatched by synchro rings also called blocker rings. Notice, before locking and speed synchronization, a lot of shearing takes place at the interfaces and for the reasons given above. Most synchronizer materials are of brass, but newer synchronizers can be made of strengthened graphite composites. Lubricant effects: A special Friction Modifier (FM) additive is incorporated into the base oil to allow just the right amount of friction before engagement. I.E., the FM gives rise to a specific coefficient of friction (COF) to allow engagement without “crunching.” Automatic Transmission Fluids (ATF) DO NOT have these specialized FM’s. Note, the specialized FM used in manual transmissions is NOT the same FM used in Limited Slip Differentials, nor is it the same FM used in Automatic Transmissions, nor is it the same FM used in engine oils. It is important to understand that there are different FM chemistries for different automotive applications!

Bearings: Lubricated bearings are used to reduce friction between rotating parts. The older Munice transmissions, for example, used brass or sintered brass sleeve bearings or bushings. Most modern transmission bearings today, as can be seen by the links given below, are of two main types 1) Roller or needle bearings, and 2) ball bearings. Ball bearings or tapered roller bearings are usually used at the shaft ends to resist radial and transverse loads. Smaller roller or pin bearings are used inside the driven gears that reside on the output shaft. Lubricant effects: Depending on the horsepower transmitted and the size of the bearings, the lubricant’s kinematic viscosities range from 7.5 cSt (ATF-range) to 14.5 cSt (equivalent to a light 75W90 gear lube) given at 100C. The anti-wear/Extreme pressure additives keep wear in check as they rotate in their races. Anti-corrosion additives keep the anti-wear/Extreme Pressure additives from attacking the synchronizers, and anti-rust additives keep any moisture from creating rust on the steel components. For lower horsepower drive trains, the lubricant must be thin enough to penetrate the cages in the pin/roller bearing areas. For higher horsepower drive trains, the lubricant must maintain a thick film in order to protect the bearing surfaces. Too thick a lubricant will cause poor cold weather performance and loss of mpg, while too thin a lubricant will cause undue wear. Of course, the lubricant is also used for cooling. The lubricant transfers heat from the bearings and gearing to the case where it is transferred to the air.

Gearing: Most gear types in manual transmissions are of the helical type, which because of the cut, reduce noise and vibration. Due to their angular cut, thrust loads are transmitted to the shafts on which they reside. The gears on the input and output shafts are usually produced in one integrated piece, called “gear clusters, “ or the cluster gear assembly. You will notice the only gear that is actually moved is the reverse idler gear. This is moved into position to mesh with the small reverse gear on the input shaft so you can “back up” or reverse direction. At higher reverse speeds, this gear will usually give off the familiar “reverse” whine. Lubricant effects: Being in constant mesh, they are dipping in the oil bath and slinging the oil up to the shifter assembly. Since they transmit torque, they must have an anti-wear/Extreme Pressure additive in the lubricant in order to reduce wear. The slipping and rolling action of the gear teeth causes localized high pressures and heating. The anti-wear/Extreme Pressure additive forms a protective but complex ferrous film at the contact surface to protect from galling and other wear mechanisms. Other components such as thrust washers, flat thrust bearings of the roller type, and shims may also need cooling, lubricant film, and anti-wear additives as well.

Rebuilding manual transmissions usually require only a modest rebuild kit consisting of bearings, synchronizers, and seals unless the transmission has been abused or the wrong lubricant has been used. In that case, gear teeth need to be examined for any chipping, galling, breakage, or other signs of problems.

(Transmission Kits).
http://www.manualtransmissionkits.com/nv4500_bk308ws_bearing_kit_rebui.htm

Here are some individual transmission parts layed out for Jeep transmissions but is typical of others.
http://www.4wd.com/Transmission-and-Transfercase/Manual-Transmissions.aspx?t_c=69&t_s=239

Images of Manual Transmissions, both external and internal:
http://www.bing.com/images/search?q=manu...ORM=IGRE#x0y810

If you are going to modify or rebuild your Manual Transmission, I highly recommend this book or equivalent::
http://www.mre-books.com/transmissions/rebuild_and_modify.html

Passing Thoughts

One variation on the Manual Transmission is the “Automated Manual” using a dual clutch. Some people consider many of the Honda Automatic Transmissions simply automated manual’s as well.
http://www.allpar.com/corporate/auto-manual-transmission.html

A long winded History and Summary but without the in-depth knowledge of internal mecahnics-vs-lubricants:
http://dictionary.sensagent.com/Manual_transmission/en-en/

I like this link; it contains online MT manuals for classic Chevy’s:
http://chevy.oldcarmanualproject.com/trans/index.htm
 
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
 
Here is what application-specific (Dedicated) MTLs consist of:

1. Base oils of various types and viscosities to make a specific viscosity and have anti-shear properties

2. GL-4 Performance Improvement (PI additive package) chemistry which consists of the following
a) GL-4 anti-wear (AW) additives
b) anti-rust additive
c) copper and aluminum metal deactivator/buffering agent
d) anti-foamant
e) special friction modifier (FM)
f) dye


Application Specific = Dedicated.
 
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Originally Posted By: MolaKule
GL-4 is a level of protection rating for gears and is generally applied to manual transmissions and to manual transaxles that do not have hypoid designs.

The older formulations in GL-4 MT lubes had about 1200 to 1500 ppm of phosphorous and zinc or ZDDP as the primary Anti-Wear additive. Some simply contained a lower level of phosphorous-sulfur EP additives like those used in differential (GL-5) lubes.

GL-4 MT lubes don't need a strong EP additive level like the phosphorous-sulfur EP levels in a differential lubricant because of the type of gearing and gear-tooth loading.

If you care to read the White Papers you will see that gear lubes, whether GL-4 or GL-5, have more than just Anti-Wear (AW) or Extreme-Pressure (EP) additives.

ALL Gear lubes contain anti-rust, anti-foam, and Metal Deactivator chemistries.

Metal Deactivator chemistries are chemical compounds that keep an additive component or contaminant from reacting with metals in the gear box.

The important thing to keep in mind about the Specific Application GL-4 MT lubes is that they contain the proper friction modifier chemistries to assist with better shifting and synchro engagement.

Personally, I relegate GL-5 rated lubes to hypoid differentials only.




Mola, Im reviving this because I recently saw an RX8 UOA side by side of RL MT-90 versus Swepco 201 (GL4 MT specific 75w90 versus a GL5 general purpose 80w90) where the Swepco showed significantly less wear metal occurrence versus the RL. GL4 75w90 is spec'd by the OEM. I would expect that the GL5 or non MT specific to have generated more metals in the UOA given its not MT specific or GL4, Can you tell me what I might be missing here?

Thank you
 
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Quote:
Mola, Im reviving this because I recently saw an RX8 UOA side by side of RL MT-90 versus Swepco 201 (GL4 MT specific 75w90 versus a GL5 general purpose 80w90) where the Swepco showed significantly less wear metal occurrence versus the RL. GL4 75w90 is spec'd by the OEM. I would expect that the GL5 or non MT specific to have generated more metals in the UOA given its not MT specific or GL4, Can you tell me what I might be missing here?


I haven' see the UOA's nor the age, driving conditions, and otherwise the history and backgrounds of these trannies so I cannot make a comment without that data.
 
Here is an updated list of MTLs:


Quote:
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 2) 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 75W80

2. Amsoil MTL (9.7 cSt)

3. GM Synchromesh’s

4. Volvo MTF 645

5. Ford Motor Craft XT-M5-QS

6. Fuchs TITAN SINTOFLUID SAE 75W-80 synthetic MTF


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 13.9 cSt

2. Redline MT-90 15.6 cSt

3. Castrol Syntrans Multivehicle 75W-90

4. Castrol Syntrans Transaxle 75w-90
 
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Updated Listing:

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:


Quote:
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 2) 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. Valvoline MTF Part Number 811095 9.2 cSt

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


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

1. Redline MTL 75W80

2. Amsoil MTL

3. GM Synchromesh’s

4. Volvo MTF 645

5. Ford Motor Craft XT-M5-QS

6. Fuchs TITAN SINTOFLUID SAE 75W-80 synthetic MTF

7. Lodexol (Morris Lubricants) MTF

I. The next higher viscosity MTL would be:

1. Redline MT-85 – 12.0 cSt


J. The next higher viscosity MTLs would be:

1. Amsoil MTG

2. Redline MT-90

3. Castrol Syntrans Multivehicle 75W-90

4. Castrol Syntrans Transaxle 75w-90
 
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Does anyone here know the full story on B.5 above - GM Manual Transmission and Transfer Case Fluid?

What I've read about it, and the applications that it's spec'd all indicate that it's the fluid formerly known as Dexron III with a new name (but without a new formula). For instance, it's GM's factory fill for the Tremec TR6060 in the Corvette and Camaro (among other models). FF used to be Dex III and before that it was Dex II. The same gearbox used by Ford and Chrysler are filled with Mercon V and ATF+4 respectively. Even Tremec themselves say "use Dexron III" in all their literature.
 
The grapevine info I got was that they increased the phosphorous AW component when they changed the labeling.

Since there are better application specific MTL fluids than DexronIII for MTLs, I don't know why anyone would use it in any MTL.
 
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