GM/AC Delco Synchromesh vs. Friction Modified version - difference?

[ringmaster]

I want to try the GM/AC Delco/Pennzoil/Quaker (I think it is all the same?) Synchromesh oil in the transmission of a Talon and an NSX.

GM offers two versions:

Synchromesh - GM part# 12345349 or AC-Delco part# 10-4006

Synchromesh Friction Modified - GM part# 12377916 or AC-Delco part# 10-4014

Does anyone know the difference? What does "friction modified" mean? Both these cars are transaxle type and both suffer from weak synchros that like to grind. It has been suggested that the FM version helps shifting but might cause more internal wear.

Thoughts or advice?

 

[Greaser]

E-mail or call the 800 number on the container.I use the Mopar fluid or the Quaker state syncromesh for my Jeep tranny.The QS fluid has a number on the container for consumer information..1-800-best-oil ...this QS fluid has only the GM part #12345349 (spec. 9985648) or GM. # 12345577 and Chrysler 4874464 spec MS9224 fluids on the back.

 

[Tremo]

I think the more important question is what kind of oil does your owner's manual tell you to use in there? ATF? Heavy gear oil? "Synchromesh" oil?

If the owner's manual calls for 75W-90 for example, then I wouldn't use anything but that. OTOH, if the manual calls for ATF, then there's a lot of options, like M1 ATF, RP Synchromax, etc....

 

[ringmaster]

quote:

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Originally posted by Tremo:
I think the more important question is what kind of oil does your owner's manual tell you to use in there? ATF? Heavy gear oil? "Synchromesh" oil?

If the owner's manual calls for 75W-90 for example, then I wouldn't use anything but that. OTOH, if the manual calls for ATF, then there's a lot of options, like M1 ATF, RP Synchromax, etc....

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I am not sure that I understand your post. The Talon calls GL-4 75W90 and the NSX normally takes 5W30 motor oil (IIRC). It is my understanding that the Synchromesh products in question are 100% safe for use in both of these transaxles.

 

[Greaser]

Who told you that the Syncromesh was the right fluid for your applications?Use what the owners manual recommends.My owners manual specs the syncromesh part numbers on the back of the container and thats what I use.

 

[Tremo]

quote:

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Originally posted by ringmaster:
I am not sure that I understand your post. The Talon calls GL-4 75W90 and the NSX normally takes 5W30 motor oil (IIRC). It is my understanding that the Synchromesh products in question are 100% safe for use in both of these transaxles. [/QB]

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OK, if the Talon wants a GL4 75W90, then that's what you should use, not GM's Synchromesh oil. For that application, I'd look seriously at Royal Purple MaxGear 75W-90, which is GL4 (non corrosive) and GL5 approved. I think Redline makes a lube with similar specs as well.

If the NSX wants 5W30 engine oil, then I'd use M1 5W30. And not GM Synchromesh.

Pay attention to your owner's manual and it's recommendations. Careless experimentation can lead to costly repairs, which would make you look like a goof.

 

[FazerZ]

GM synchromesh fluid (OE#12345349) is actually a excellent substitute for SOME applications requiring 75W90 gear oil.

For example, Jeep vehicles that use the Aisin Warner AX-5 and AX-15 spec out 75W90 gear oil for that application, however in certain colder climates, customers can get shift difficulties until the vehicle warms up.

At our shop, we have been able to eliminate these cold complaints by using the GM synchromesh fluid (OE#12345349) with excellent results. This was brought about by recommendations by multiple part vendors.

On our AX-5/AX-15 overhauls, we use this fluid with no ill effects and the fill seems to work better than the factory spec'ed fill. For us, this is a better fill for these transmissions.

HOWEVER, i do not recommend experimenting without some proper background information and real world usage experience. There are many documented cases where the wrong fluid usage has major detrimental consequences.

The OE recommended fluid is always the safest route, however not the best and only solution.

The GM friction modified synchromesh fluid (OE#12377916) is used in a select crop of New Venture units that have friction lined blocker rings that need the additive package present. I am aware of no other uses for this fluid besides the stock applications.

 

[Johnny2Bad]

" AC Delco Synchromesh Transmission Fluid" ... General Motors Canada Part # 89021808
" AC Delco Synchromesh Transmission Fluid - Friction Modified" -GM USA Part # 10953509

Difference between the above is labelling to meet national standards.

GM Friction Modified - #12377916 is an old part # and the above replaces it.

The MSDS for the above lists the product as "Shell MTX Fluid", and that is confirmed by Shell documentation.

Shell documentation shows is also sold by Chrysler dealers as "SYNCHROMESH TRANSMISSION FLUID" Code 1874 MTX Fluid; MOPAR Part # 4761526

The fluid is a popular recommended MTF in Getrag transmissions, Honda, and Mazda 5 and 6 speeds. Users generally report better shift feel at all operating temperatures and better low-temperature performance at cold-start.

Also it is used as the bulk fill fluid at some Mazda dealers (confirmed for Burlington Mazda (Toronto) and Mountain Mazda (Hamilton ON).

I have also heard anecdotal reports that Honda approves it's use and accepts it as warranty-approved, but that should be confirmed by the user by talking to Honda.

 

[Johnny2Bad]

FWIW, another popular Manual Transmission Fluid amongst the same crowds as above is Motorcraft XT-M5-QS (available at Ford dealers).

Cost is about the same as the GM / AC Delco MTF. If you find the GM / Shell / Mopar / Motorcraft for less than about $25/qt/l then you are getting a good price.

The Motorcraft MTF is for some Ford Focus models that use a Getrag transmission. Because its so specific, it may be hard to find but Ford dealers seem to be happy to order it for you.

With any of the above I have no information or advice to offer regarding use in differentials.

Also, it may be worth mentioning that with regard to Engine Oils used as a Gear Lube that the viscosity rating for Motor Oil and Gear Lubricants are not equivalent ... ie a 50 WT Motor Oil is not 50 WT Gear Oil. I would suggest getting full documentation and check all the viscosity data if you are considering using Motor Oil in a transmission.

 

[JamesBond]

I'm not sure what the difference is between the two but I've heard Pennzoil Synchromesh is the same as the regular GM one.

I've used this fluid in a Civic, Celica, Ranger and BMW and have had good shifting in all of them. I think its about a 5w-30 weight which is thick for the Ranger and thin for the Celica but not by much and it works well. The bottle says its safe for yellow metals also.

Plus its available at most parts stores and is cheaper than the GM stuff.

 

[Johnny2Bad]

Yes, I have also heard that the "regular" MTF is made by Penzoil, but I have not been able to confirm it. Perhaps someone will be willing to do some digging.

As for viscosity, I have compared the Friction Modified MTF against Mobil1 15W-50. The FM is lower viscosity at lower temps but carries a higher Viscosity Index. Just an example where viscosity has to be carefully researched; charts would be best. Perhaps the 5W-30 would be a closer match but you'd have to confirm it to determine how close.
FM -- * Mobil1 *

cSt at 40°C: 41.6 -- * 125 *
cSt at 100°C: 9.08 -- * 18 *
Viscosity Index: [Method D 2270] 208 -- * 160 *

 

[dailydriver]

So is the friction modified GM fluid the ONLY one of those which is semi-synthetic (since we've determined long ago that the Pennzoil stuff is ALL mineral based)???

Also; does anyone know which of the various GM friction modded fluids would be best for a 2000 vintage, Tremec T56 (IF any)??

 

[RustyH]

I have used a few different MTFs in my 2002 BMW 530. Love the GM Synchromesh-Friction Modified. I purchase it in an AC Delco bottle, part no. 10-4014 (88900399). Never tried the other GM product and probably won't. I have not tried the Pennzoil product nor any Red line products just the BMW MTF-2, Royal Purple, Amsoil.

 

[bmwtechguy]

I would use the Amsoil MTF, which is a fully formulated synthetic manual transmission "synchromesh" fluid that is designed to work well with friction needs of synchronizers and a great all-temp fluid. Not nearly as expensive as dealer stuff and performs as well or better for me.

 

[aquariuscsm]

You can use Pennzoil Synchromesh to help gear grind,especially if it`s the 1>2 shift. Try Amsoil MTG first and see how it works.

 

[bmwtechguy]

The Amsoil MTG is a heavier 75W-90 GL4 gear oil for manual transmissions and the MTF is a lighter, synchromesh manual transmission fluid. Depending on which viscosity it calls for, one may work better than the other, but both work really well with synchronizers in a manual gearbox.

 

[MolaKule]

Quote:
Does anyone know the difference? What does "friction modified" mean? Both these cars are transaxle type and both suffer from weak synchros that like to grind. It has been suggested that the FM version helps shifting but might cause more internal wear.


What vehicle and how many miles?

Both GM MTL's have synchro Friction modifiers but the later MTL has a special polymer friction modifier.

If these vehicles are transaxle types, they usually specify 75W90 (14.5 cSt) viscosity MTL's because of the spider gear differentials in those transaxles.

The GM MTL's, the Amsoil MTF, and the Redline MTL 70W80 are all 10.5 cSt lubes.