I have a 2006 GMC Sierra with a NV3500 tranny and GM recommends Synchromesh Fuid #12345349.
Is there another oil I could use here? The Synchromesh fluid is expensive.
Is there another oil I could use here? The Synchromesh fluid is expensive.
GM Synchromesh Fluid
- Thread starter George7941
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Originally Posted By: George7941
I have a 2006 GMC Sierra with a NV3500 tranny and GM recommends Synchromesh Fuid #12345349.
Is there another oil I could use here? The Synchromesh fluid is expensive.
I used Pennzoil Synchromesh fluid in my 00 Silverado with excellent results. Its only $3 a quart at AutoZone or Checkers.
I know things are more expensive but check what a few quarts of that would cost.
Bill
I have a 2006 GMC Sierra with a NV3500 tranny and GM recommends Synchromesh Fuid #12345349.
Is there another oil I could use here? The Synchromesh fluid is expensive.
I used Pennzoil Synchromesh fluid in my 00 Silverado with excellent results. Its only $3 a quart at AutoZone or Checkers.
I know things are more expensive but check what a few quarts of that would cost.
Bill
MolaKule
Staff member
Hi George; here is some info for you:
Quote:
A synchromesh GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (ATF equivalent viscosity) to a 75W90 type viscosity of approx. 14.5 cSt, and contains special friction modification additives for synchronizer assembly engagement.
A synchromesh fluid usually refers to a specialized fluid that contains special friction modification additives for transmissions that use mechanical synchronizer assemblies; those synchronizer assemblies may be made of carbon fiber composites, sintered metal, brass/bronze, or steel-steel materials.
Current synchromesh MTL GL4 viscosites are:
1. ATF Series - Type; 6.5 to 8.5 cSt (Equivalent ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series - Type; 9.3 - 9.5 cSt (such as Amsoils MTF, Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt ( Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).
MTL specific lubes we're developed for manual tranny's and transaxles, and not for differentials or industrial gear boxes, so their viscosities will not match most viscosity charts.
Quote:
A synchromesh GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (ATF equivalent viscosity) to a 75W90 type viscosity of approx. 14.5 cSt, and contains special friction modification additives for synchronizer assembly engagement.
A synchromesh fluid usually refers to a specialized fluid that contains special friction modification additives for transmissions that use mechanical synchronizer assemblies; those synchronizer assemblies may be made of carbon fiber composites, sintered metal, brass/bronze, or steel-steel materials.
Current synchromesh MTL GL4 viscosites are:
1. ATF Series - Type; 6.5 to 8.5 cSt (Equivalent ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series - Type; 9.3 - 9.5 cSt (such as Amsoils MTF, Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt ( Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).
MTL specific lubes we're developed for manual tranny's and transaxles, and not for differentials or industrial gear boxes, so their viscosities will not match most viscosity charts.
Molakule.
Do you know if Redline MTL 75W85 will be too thick for the NV3500?
Do you know if Redline MTL 75W85 will be too thick for the NV3500?
George the MTL is a great oil for a NV3500 along with Amsoil's MTF. Some people rave about the Pennzoil Syncromesh as well. The Amsoil and Redline oils do not shear as easily as the Pennzoil and provide butter smooth shifting over a longer oci. Also the Redline MTL oil is slightly thicker than the Amsoil MTF.
George - There is not a huge difference between the Synchromesh and the Redline MTL. The only time it would be of any consequence is when it is super cold out, and you may notice it . But any gear oil thickens when cold, anyway. Being a full synthetic, it may not even be noticeable.
Originally Posted By: mikey12
Avoid a GL-5 rated gear lube in a Synchromesh spec tranny as it is reactive to yellow metal. An MTL rated oil that is also not rated GL-5 is suitable. GL-5 additives contain sulfur.
Modern gear oil is not considered corrosive to yellow metals. GL-4 usually contain sulfur as well, just less of it.
GL-5 are usually not built for good shifting, however.
Avoid a GL-5 rated gear lube in a Synchromesh spec tranny as it is reactive to yellow metal. An MTL rated oil that is also not rated GL-5 is suitable. GL-5 additives contain sulfur.
Modern gear oil is not considered corrosive to yellow metals. GL-4 usually contain sulfur as well, just less of it.
GL-5 are usually not built for good shifting, however.
I was always told the same thing as Mikey12 has posted. Here is something showing true on what Tempest said.
http://www.practicingoilanalysis.com/article_detail.asp?articleid=496&relatedbookgroup=OilAnalysis
Modern gear lube additives contain sulfur-phosphorus components that are thermally stable, and are noncorrosive to bronze and other nonferrous metals.
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.
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Modern EP gear oils contain thermally stable additives that promote system cleanliness and do not corrode yellow metals under moderate operating conditions. The goal in formulating top-tier EP gear oils is to develop additive chemistries that will carry high loads under boundary conditions and protect mating surfaces from wear while minimizing corrosiveness to yellow metals and keeping steel gear components clean.
http://www.practicingoilanalysis.com/article_detail.asp?articleid=496&relatedbookgroup=OilAnalysis
Modern gear lube additives contain sulfur-phosphorus components that are thermally stable, and are noncorrosive to bronze and other nonferrous metals.
.
.
.
Modern EP gear oils contain thermally stable additives that promote system cleanliness and do not corrode yellow metals under moderate operating conditions. The goal in formulating top-tier EP gear oils is to develop additive chemistries that will carry high loads under boundary conditions and protect mating surfaces from wear while minimizing corrosiveness to yellow metals and keeping steel gear components clean.
Kestas
Staff member
The news of this trend is comforting. Since old habits and ideas die hard, I'd still look at the product information for the specific lube to see how it addresses the issue of brass components.
Good point Kestas. Checking the ASTM D-130 (Copper Corrosion)score for a gear lube is a good idea before pouring it into a yellow metal situation.
In my 99 S10 with a similar NV1500 transmission I used Honda MTF, which is way cheaper than the synchromesh. It works perfectly, no problems so far with 10.000 km (6250 miles). Changes are smooth when cold and hot.
oravla - Gm Synchromesh is much higher priced than the almost identical Pennzoil Synchromesh.
MolaKule
Staff member
Oravia and others:
Hopefully you have seen this little informational piece:
Quote:
Most differential and Manual Transmission oils contain sulfur-phosphorous EP packages. GL4-rated oils contain about 40% to 60% of that amount; the other difference is the Friction Modifier.
Both differential and manual transmission fluids use chemical compounds that subdue or inhibit the corrosive effects of sulfur such as calcium, magnesium, boron, potassium or other basic compounds. Emulsifiers, corrosion and rust inhibitors also are included to do their respective jobs.
Differential lubes use friction modifiers to reduce mechanical and fluid friction and add some anti-shudder friction modifier for limited slip, both very different chemical compounds.
Manual Transmission fluids use a different friction modifier for synchro engagement, a modifier that does NOT contain the same chemicals as differential lubes.
Differential lubes use friction modifiers to reduce mechanical and fluid friction and add some anti-shudder friction modifier for limited slip, both very different chemical compounds.
Manual Transmission fluids use a different friction modifier specifically designed for synchro engagement, a modifier that does NOT contain the same chemical compounds as do differential lubes.
Both lubes generally contain the same TYPE EP additives, just in different strengths or additive ratios.
Most manual transmission "specific" fluids (GL4) contain about 40% to 60% of the EP additive of differential lubes (GL5) with inactive or buffered sulphurs. GL4 has come to infer a gear lube with the above percentages of EP additive. The exception of course is ATF fluid used in some of the newer transmissions.
You also have to consider the viscosity of the fluid that the transmission was designed for. The spectrum now ranges from ATF to 75W90 viscosities.
Ever since the synchromesh-type fluids appeared on the scene (such as the GM Synchromesh fluid), drivers have had better shifting due to better synchro engagement, attributed to the specialized friction modifier used in these lubes. This specialized friction modifier is better for metallic and composite synchros in terms of shifting and life.
A diffy 75W90 (GL5) usually has a higher viscosity than does an mtl in the same advertized weight.
So a differential lube may not kill your tranny, but it is not the optimum lube.
GL4 does NOT refer to any specific viscosity, but it refers to a level of AW/EP protection for the gearing and bearings in a transmission.
A synchromesh GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (ATF equivalent viscosity) to a 75W90 type viscosity of approx. 14.5 cSt, and contains special friction modification additives for synchronizer assembly engagement.
A synchromesh fluid usually refers to a specialized fluid that contains special friction modification additives for transmissions that use mechanical synchronizer assemblies; those synchronizer assemblies may be made of carbon fiber composites, sintered metal, brass/bronze, or steel-steel materials.
Current MTL GL4 viscosites are:
1. ATF Series - Type; 6.5 to 8.5 cSt (Equivalent ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series -Type; 9.3 - 9.5 cSt (such as Amsoils MTF, Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt ( Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).
MTL specific lubes we're developed for manual tranny's and transaxles, and not for differentials or industrial gear boxes.
Hopefully you have seen this little informational piece:
Quote:
Most differential and Manual Transmission oils contain sulfur-phosphorous EP packages. GL4-rated oils contain about 40% to 60% of that amount; the other difference is the Friction Modifier.
Both differential and manual transmission fluids use chemical compounds that subdue or inhibit the corrosive effects of sulfur such as calcium, magnesium, boron, potassium or other basic compounds. Emulsifiers, corrosion and rust inhibitors also are included to do their respective jobs.
Differential lubes use friction modifiers to reduce mechanical and fluid friction and add some anti-shudder friction modifier for limited slip, both very different chemical compounds.
Manual Transmission fluids use a different friction modifier for synchro engagement, a modifier that does NOT contain the same chemicals as differential lubes.
Differential lubes use friction modifiers to reduce mechanical and fluid friction and add some anti-shudder friction modifier for limited slip, both very different chemical compounds.
Manual Transmission fluids use a different friction modifier specifically designed for synchro engagement, a modifier that does NOT contain the same chemical compounds as do differential lubes.
Both lubes generally contain the same TYPE EP additives, just in different strengths or additive ratios.
Most manual transmission "specific" fluids (GL4) contain about 40% to 60% of the EP additive of differential lubes (GL5) with inactive or buffered sulphurs. GL4 has come to infer a gear lube with the above percentages of EP additive. The exception of course is ATF fluid used in some of the newer transmissions.
You also have to consider the viscosity of the fluid that the transmission was designed for. The spectrum now ranges from ATF to 75W90 viscosities.
Ever since the synchromesh-type fluids appeared on the scene (such as the GM Synchromesh fluid), drivers have had better shifting due to better synchro engagement, attributed to the specialized friction modifier used in these lubes. This specialized friction modifier is better for metallic and composite synchros in terms of shifting and life.
A diffy 75W90 (GL5) usually has a higher viscosity than does an mtl in the same advertized weight.
So a differential lube may not kill your tranny, but it is not the optimum lube.
GL4 does NOT refer to any specific viscosity, but it refers to a level of AW/EP protection for the gearing and bearings in a transmission.
A synchromesh GL4 Manual Transmission Lubricant (MTL) can be any viscosity from 7.0 cSt (ATF equivalent viscosity) to a 75W90 type viscosity of approx. 14.5 cSt, and contains special friction modification additives for synchronizer assembly engagement.
A synchromesh fluid usually refers to a specialized fluid that contains special friction modification additives for transmissions that use mechanical synchronizer assemblies; those synchronizer assemblies may be made of carbon fiber composites, sintered metal, brass/bronze, or steel-steel materials.
Current MTL GL4 viscosites are:
1. ATF Series - Type; 6.5 to 8.5 cSt (Equivalent ATF viscosity; Note: ATF additive package is weak compared to most GL 4's)
2. Synchromesh Series -Type; 9.3 - 9.5 cSt (such as Amsoils MTF, Texaco's MTL, Pennzoil's Synchromesh, GM and Chrysler's Synchromesh)
3. 75W85 Series-Type; 9.8 to 11.5 cSt ( Redline's MTL, RP's Synchromax LT, Nissan's MTL, Honda MTL, Castrol Syntorq LT)
4. 75W90 Series-Type; 12.8 to 14.5 cSt (Amsoil's MTG, Redline's MT-90).
MTL specific lubes we're developed for manual tranny's and transaxles, and not for differentials or industrial gear boxes.
Last edited:
Very informative post, Molakule. It furthered my knowledge of tranny and diff lubes.
I have one question regarding your statement
"A diffy 75W90 (GL5) usually has a higher viscosity than does an mtl in the same advertized weight."
Isn't a spec like 75W90 a measure of the viscosity of the oil? I have always assumed that the 'weight' of an oil referred to its viscosity. Shouldn't two oils of the same weight rating have roughly the same viscosity?
I have one question regarding your statement
"A diffy 75W90 (GL5) usually has a higher viscosity than does an mtl in the same advertized weight."
Isn't a spec like 75W90 a measure of the viscosity of the oil? I have always assumed that the 'weight' of an oil referred to its viscosity. Shouldn't two oils of the same weight rating have roughly the same viscosity?
MolaKule
Staff member
Quote:
Isn't a spec like 75W90 a measure of the viscosity of the oil? I have always assumed that the 'weight' of an oil referred to its viscosity. Shouldn't two oils of the same weight rating have roughly the same viscosity?
Any lubricant viscosity chart such as
http://www.bobistheoilguy.com/visc.html
or
http://www.lubricon.ca/doc_bin/ViscositiesChart.pdf
or
http://www.powerstrokenation.com/forums/showthread.php?t=1503
you will see that any so-called lubricant "weight" can have a variance or "delta" in kinematic viscosity in cSt.
The 75W90 mt lubes generally have a kinematic viscosity of about 14.5@100C on the low end or the equivalent of an 85 weight at a temperaure of 100C.
INHO, the term "weight" should be discarded as OBSOLETE and we should speak in terms of kinematic viscosity in cSt.
Isn't a spec like 75W90 a measure of the viscosity of the oil? I have always assumed that the 'weight' of an oil referred to its viscosity. Shouldn't two oils of the same weight rating have roughly the same viscosity?
Any lubricant viscosity chart such as
http://www.bobistheoilguy.com/visc.html
or
http://www.lubricon.ca/doc_bin/ViscositiesChart.pdf
or
http://www.powerstrokenation.com/forums/showthread.php?t=1503
you will see that any so-called lubricant "weight" can have a variance or "delta" in kinematic viscosity in cSt.
The 75W90 mt lubes generally have a kinematic viscosity of about 14.5@100C on the low end or the equivalent of an 85 weight at a temperaure of 100C.
INHO, the term "weight" should be discarded as OBSOLETE and we should speak in terms of kinematic viscosity in cSt.
Last edited:
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