Manual Transmission Fluids - Updated

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MolaKule

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Posting it here since people new to BITOG do not look in the White Papers forum. Manual Transmission (MT) Lubricants (Updated 2/9/2017) Ever since dedicated MT fluids appeared on the scene (such as the GM Synchromesh series of fluids), 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 [email protected] 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 [email protected] 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 GL-5 rated MT fluids 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 and force of parts that mesh and de-mesh during engagement and disengagement. (For a similar discussion of ATF’s and friction modification, please see: https://bobistheoilguy.com/forums/ubbthr...ion#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 [email protected] 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 [email protected] For example, if your transmission requires a [email protected] 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. Rather recently, many MT manufacturers have introduced fluid specifications for fluids with lower viscosities in the range of [email protected] to [email protected], 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 we're 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. Feel free to comment, ask questions, or to discuss new MT fluids.
 
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Thanks for the informative article. I'm curious what you would recommend for my '67 Belvedere's 3-speed. When the car was new, Chrysler recommended ATF, with a note to use SAE90 gear oil (!) if there was gear rattle.
 

MolaKule

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Originally Posted By: zrxkawboy
Thanks for the informative article. I'm curious what you would recommend for my '67 Belvedere's 3-speed. When the car was new, Chrysler recommended ATF, with a note to use SAE90 gear oil (!) if there was gear rattle.
Hmmm! I had a '65 Chevy with a 327 and a Muncie 3-Speed and they recommended a 90 grade gear oil, as did most manf. of that era. If the tranny doesn't have a lot of wear (is not loosey-goosy), try the Pennzoil Synchromesh, Valvoline MTF, or the GM Synchromesh. I hesitate to recommend the newer synthetic MTF's of 75W85 or 75W90 because those old seals may not be compatible with synthetics.
 
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I have a 91 dodge dakota 4 cy 5 speed that is specified for 10w40 SE motor oil. Currently using 10W40 motorcycle oil. Does not shift the best, maybe because it had GL5 90 wt which may have damaged the syncros. Any recommendations? Rod
 
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Originally Posted By: MolaKule
try the Pennzoil Synchromesh, Valvoline MTF, or the GM Synchromesh.
Will do. Thank you, sir!
 

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Originally Posted By: ragtoplvr
I have a 91 dodge dakota 4 cy 5 speed that is specified for 10w40 SE motor oil. Currently using 10W40 motorcycle oil. Does not shift the best, maybe because it had GL5 90 wt which may have damaged the syncros. Any recommendations? Rod
Any of these should work: 1. Redline MT-85 2. Amsoil MTG 3. Redline MT-90 4. Ford MOTORCRAFT® XT-75W90-QGT or Full Synthetic Manual Transmission Fluid XT-M5-QS 5. Castrol Syntrans Multivehicle 75W-90 6. Castrol Syntrans Transaxle 75w-90
 
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The Z31 versions of my car used the T5 manual transmissions.There was a sticker on the transmission that said "Fluid type-Dexron or 80W90 GL4". I wonder why such two different fluid recommendations?
 

MolaKule

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Originally Posted By: aquariuscsm
The Z31 versions of my car used the T5 manual transmissions.There was a sticker on the transmission that said "Fluid type-Dexron or 80W90 GL4". I wonder why such two different fluid recommendations?
Typical Tremec/GM vascillation. I would think that a fluid such as Redline MTL 75W80 or Redline MT-85 would provide sufficient protection.
 
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Originally Posted By: MolaKule
Posting it here since people new to BITOG do not look in the White Papers forum. Manual Transmission (MT) Lubricants (Updated 2/9/2017) Ever since dedicated MT fluids appeared on the scene (such as the GM Synchromesh series of fluids), 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 [email protected] 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 [email protected] 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 GL-5 rated MT fluids 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 and force of parts that mesh and de-mesh during engagement and disengagement. (For a similar discussion of ATF’s and friction modification, please see: https://bobistheoilguy.com/forums/ubbthr...ion#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 [email protected] 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 [email protected] For example, if your transmission requires a [email protected] 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. Rather recently, many MT manufacturers have introduced fluid specifications for fluids with lower viscosities in the range of [email protected] to [email protected], 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 we're 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. Feel free to comment, ask questions, or to discuss new MT fluids.
Nice job MolaKule !!
 
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Originally Posted By: MolaKule
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.
Molakule, very nice job updating this white paper. Concerning the Tremecs above, what is your current best, recommended fluid for their earlier synchronizers of the cellulose lined/kevlar/graphite composite? Tremec only formally recommends conventional ATF's or M1 synthetic ATF, the only ones they've bothered testing. On your list of lubricants below in that viscosity range GM's MTL shows up, though it's really only an ATF with a little extra phosphorus/boron...probably even less of it than what is seen in the synthetic ATF's (M1 ATF, RedLine D4, Amsoil ATD, RP Synchromax). The Tremecs with the post-2000 carbon blocker rings seem to do fine on the Synchromeshes, even if Tremec doesn't recommend it. B. The next higher viscosity MTL would be the 7.0 to 7.5 [email protected] versions [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 7. Tutelo (Petronus, Italy, Product Code 1402) 8. Pentosin Pro Gear 70W75 (Australia) The full MTF list from the old WP thread might be a good list to link to this WP in order that everything is available in one look.
 

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Originally Posted By: 69GTX
Originally Posted By: MolaKule
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.
Molakule, very nice job updating this white paper. Concerning the Tremecs above, what is your current best, recommended fluid for their earlier synchronizers of the cellulose lined/kevlar/graphite composite? Tremec only formally recommends conventional ATF's or M1 synthetic ATF, the only ones they've bothered testing. On your list of lubricants below in that viscosity range GM's MTL shows up, though it's really only an ATF with a little extra phosphorus/boron...probably even less of it than what is seen in the synthetic ATF's (M1 ATF, RedLine D4, Amsoil ATD, RP Synchromax). The Tremecs with the post-2000 carbon blocker rings seem to do fine on the Synchromeshes, even if Tremec doesn't recommend it. B. The next higher viscosity MTL would be the 7.0 to 7.5 [email protected] versions [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 7. Tutelo (Petronus, Italy, Product Code 1402) 8. Pentosin Pro Gear 70W75 (Australia) The full MTF list from the old WP thread might be a good list to link to this WP in order that everything is available in one look.
If under warranty, use the fluids recommended by Tremec and keep receipts, even though they recommend an out-of-date specification. If out of warranty, the above fluids up to and including the 10.5 cSt fluids should work, depending on average outside temp. As I said in the WP, one has to try different fluids because of clutch and wear condition, driving styles, mileage, average temp, etc. I attempt to update that list regularly as soon as I have verified the specifications, either through detailed manf. literature or through my own lab testing. In many cases, it is like chasing wet cats. LOL
 
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I hope the mods will sticky this thread at the top of the ATF/transmission forum so you don't have to go hunting for it down the road.
 
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Is there a suitable alternative (i.e. better) to Ford's Motorcraft XT-11-QDC DCT fluid that is used in certain Getrag 6 spd manuals?
 

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Originally Posted By: asiancivicmaniac
Is there a suitable alternative (i.e. better) to Ford's Motorcraft XT-11-QDC DCT fluid that is used in certain Getrag 6 spd manuals?
I don't know what is so bad about the Ford product in terms of performance; maybe dealer price turns you off? Here are some possible alternatives: Castrol Syntrans FE, [SAE 70W75] (~ 6.5 cSt) BMW (Pentosin) MTF-LT-3, [SAE 70W75] (~ 6.5 cSt) Honda MTII or MTF 2, [SAE 70W75] (~ 6.5 cSt) Volvo Manual Transmission Fluid, [SAE 70W75] (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] Castrol Syntrans V FE [SAE 75W80] (8.0cSt) Redline DCTF Dual Clutch Transmission Fluid [SAE 75W-80] (8.1 cSt) BG Synchroshift II [SAE 75W80] (8.2 cSt)
 
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