# Synchromesh Fluid



## ModBoss2 (Nov 13, 2005)

Anybody use it in their M6s? Or is synthetic atf still the way to go? Mike?


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## Guest (Dec 13, 2005)

synthetic is your best choice, dont fall victim to scams.


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## ModBoss2 (Nov 13, 2005)

big_mike said:


> synthetic is your best choice, dont fall victim to scams.


Nice.

I think I'll try Mobil 1 ATF, since I'm using their motor oil. My M6 feels kinda rough due to the colder temps. I might do that at 5,000 miles w/ my oil change. 1,300 miles right now.

Yes, I haven't changed the oil yet, but I did put on a new filter and topped off the oil about 100 miles ago. So far, I notice no oil consumption during this break-in period.


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## Guest (Dec 13, 2005)

good. Just keep an eye on all your fluids.


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## GTODEALER (Jan 7, 2005)

Royal Purple or Amsoil is the best way to go!


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## Guest (Dec 13, 2005)

nothing but synthetics.


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## johnebgoode (Oct 4, 2005)

ModBoss2 said:


> Nice.
> 
> I think I'll try Mobil 1 ATF, since I'm using their motor oil. My M6 feels kinda rough due to the colder temps. I might do that at 5,000 miles w/ my oil change. 1,300 miles right now.
> 
> Yes, I haven't changed the oil yet, but I did put on a new filter and topped off the oil about 100 miles ago. So far, I notice no oil consumption during this break-in period.


What I usually do with a new car is drop it at 1000 miles and cut open the filter to make sure nuthin negative is happening inside.


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## Guest (Dec 13, 2005)

thats a good idea, if you have the tools to cut a filter open.


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## johnebgoode (Oct 4, 2005)

big_mike said:


> thats a good idea, if you have the tools to cut a filter open.


Not that difficult even without the tools......... :cool


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## Guest (Dec 13, 2005)

I just dont want to see someone grab a kitchen knife and spend all day hackin....


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## johnebgoode (Oct 4, 2005)

big_mike said:


> I just dont want to see someone grab a kitchen knife and spend all day hackin....


Mike, gotta give evryone some credit as to having the potential to NOT cut off there appendages.


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## Guest (Dec 13, 2005)

some people have made bad decisions.


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## johnebgoode (Oct 4, 2005)

big_mike said:


> some people have made bad decisions.


Ya can always send over the Red Cross girl.............. :cool


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## Guest (Dec 13, 2005)

sure can, wait til you see what I put up next!


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## johnebgoode (Oct 4, 2005)

big_mike said:


> sure can, wait til you see what I put up next!


We're waiting with baited breath. I have a fish in my mouth......... :lol:


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## Guest (Dec 13, 2005)

is that what that is?


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## ModBoss2 (Nov 13, 2005)

GTODEALER said:


> Royal Purple or Amsoil is the best way to go!


I've been doing some more checking...I was originally talking about GM's and Pennzoil's Synchromesh fluid [used GM's in my fwd CSVT], then I hear that synthetic atf is best. I'm now hearing that some synthetics are actually bad for the M6's friction material, and that Royal Purple's synchromesh is a good product for our M6s. True?


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## Guest (Dec 14, 2005)

some synthetics not designed for the manual CAN cause damage as they dont have friction modifiers. Royal Purple and Amsoil are the best on the market for the entire vehicle. Pricey, but worth every penny.


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## ModBoss2 (Nov 13, 2005)

big_mike said:


> some synthetics not designed for the manual CAN cause damage as they dont have friction modifiers. Royal Purple and Amsoil are the best on the market for the entire vehicle. Pricey, but worth every penny.


Yeah, I talked about friction modifiers earlier, on a different thread [iirc :willy:], but I'm not sure that I ever got an answer on the cocktail mix. I just figured nobody used modifiers on these transmissions. I think I can get Royal Purple locally.


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## Guest (Dec 14, 2005)

GOOD, throw some purple gogo juice in there and you be rockin!


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## GTODEALER (Jan 7, 2005)

ModBoss2 said:


> I've been doing some more checking...I was originally talking about GM's and Pennzoil's Synchromesh fluid [used GM's in my fwd CSVT], then I hear that synthetic atf is best. I'm now hearing that some synthetics are actually bad for the M6's friction material, and that Royal Purple's synchromesh is a good product for our M6s. True?


I personally use Royal Purple ATF in my tranny and I will be the first to tell you I've "tested" my tranny numerous times and no issues. Remember our trannys are M12's, slightly different than the weaker M6.


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## Guest (Dec 14, 2005)

the M6 has ratios of 2.66, 1.78, 1.30, 1.00, 0.76, 0.50
the M12 has ratios of 2.97, 2.07, 1.43, 1.00, 0.84, 0.57

correct me if I am wrong, but the lower the number, the more torque it can handle. Which means, the M6 was stronger.


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## ModBoss2 (Nov 13, 2005)

GTODEALER said:


> I personally use Royal Purple ATF in my tranny and I will be the first to tell you I've "tested" my tranny numerous times and no issues. Remember our trannys are M12's, slightly different than the weaker M6.


I will be buying Royal Purple, but it will be their Synchromax. It seems to be specifically designed for manuals that were originally filled w/ atf.

b.t.w. I thought your F.B. looked and sounded good [from the recent video]


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## GTODEALER (Jan 7, 2005)

ModBoss2 said:


> I will be buying Royal Purple, but it will be their Synchromax. It seems to be specifically designed for manuals that were originally filled w/ atf.
> 
> b.t.w. I thought your F.B. looked and sounded good [from the recent video]


Thanks!


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## ModBoss2 (Nov 13, 2005)

big_mike said:


> the M6 has ratios of 2.66, 1.78, 1.30, 1.00, 0.76, 0.50
> the M12 has ratios of 2.97, 2.07, 1.43, 1.00, 0.84, 0.57
> 
> correct me if I am wrong, but the lower the number, the more torque it can handle. Which means, the M6 was stronger.


I think that's correct, because the higher the number, the more the torque is multiplied...so, :agree I think.


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## GTODEALER (Jan 7, 2005)

big_mike said:


> the M6 has ratios of 2.66, 1.78, 1.30, 1.00, 0.76, 0.50
> the M12 has ratios of 2.97, 2.07, 1.43, 1.00, 0.84, 0.57
> 
> correct me if I am wrong, but the lower the number, the more torque it can handle. Which means, the M6 was stronger.


Your wrong.... M6 is rated at 450 tq and the M12 is rated at 600...... even thought the M6 is rated less it can take more.


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## Guest (Dec 14, 2005)

well, no point in disputing the fact, I will take you for your word.

*but secretly research more*


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## Guest (Dec 14, 2005)

According to Tremec themselves, the T-56 specs found here:
http://www.tremec.com/English/products/T-56.asp

the 2.66 first ratio allows up to 550 tq. handling
the 2.97 first ratio allows up to 450 tq. handling

Just stating facts I find.


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## GTODEALER (Jan 7, 2005)

big_mike said:


> According to Tremec themselves, the T-56 specs found here:
> http://www.tremec.com/English/products/T-56.asp
> 
> the 2.66 first ratio allows up to 550 tq. handling
> ...


I've read that same thing..... and now I can't find my specs I had..... so we'll go with your #'s now.


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## Guest (Dec 14, 2005)

whats funny is the fbody got the 2.66 gear but the Z06 got the 2.97 gear. How ironic is that? Granted the 2.97 gear will make you quicker with the power you have, the 2.66 can handle more power!


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## dealernut (Oct 22, 2005)

big_mike said:


> whats funny is the fbody got the 2.66 gear but the Z06 got the 2.97 gear. How ironic is that? Granted the 2.97 gear will make you quicker with the power you have, the 2.66 can handle more power!



Bear with me guys. This is one thing about cars I still have not figured out. 


The 2.97 gear is the size of the ring on the first gear right?


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## GTODEALER (Jan 7, 2005)

Sooooo, syncromesh fluid for our trannys may potentially be better than the ATF I'm running....... interesting. Subdriver, what do you think? :cheers 
*trying to stay on topic*


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## Guest (Dec 14, 2005)

dealernut said:


> Bear with me guys. This is one thing about cars I still have not figured out.
> 
> 
> The 2.97 gear is the size of the ring on the first gear right?


Yes, the ratio of 1st determines how much the transmission can handle as thats the smallest gear out of all of them. SO, since your only as strong as your weakest link..... :seeya:


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## GTODEALER (Jan 7, 2005)

big_mike said:


> SO, since your only as strong as your weakest link..... :seeya:


I've found that way tooo many times......


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## Guest (Dec 14, 2005)

GTODEALER said:


> I've found that way tooo many times......


we know. 


dear lord heaven above do we know!!! lol


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## dealernut (Oct 22, 2005)

Ok. So a 2.66 gear means what. What does the 2.66 mean exactly. I know it is a bit off topic, but damnit this stuff always drives me nuts.


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## Guest (Dec 14, 2005)

a gear ratio is how much torque is multiplied when coming off the input shaft. SO, if you make 400lb.ft of torque, with a 2.66 gear, your rearend is seeing 1064lb.ft of torque and then its divided by your rear gear, which means your tires should see about 310-320lb.ft. of torque.

Or at least, thats how it was explained to me.


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## dealernut (Oct 22, 2005)

big_mike said:


> a gear ratio is how much torque is multiplied when coming off the input shaft. SO, if you make 400lb.ft of torque, with a 2.66 gear, your rearend is seeing 1064lb.ft of torque and then its divided by your rear gear, which means your tires should see about 310-320lb.ft. of torque.
> 
> Or at least, thats how it was explained to me.


See that makes sense. Hopefully its right. :cool


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## Guest (Dec 14, 2005)

go to a dyno and let me know.


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## ModBoss2 (Nov 13, 2005)

Another ?

Napa's pro-link shows about 4.6 qts for the manual's capacity...is that true?
Seems like a lot. I'm about to order the synchromax.


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## Guest (Dec 15, 2005)

http://www.standardtransmission.com/TTC specs.html

8.13 pints, however many quarts that is.


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## ModBoss2 (Nov 13, 2005)

big_mike said:


> http://www.standardtransmission.com/TTC specs.html
> 
> 8.13 pints, however many quarts that is.


Thanks


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## Guest (Dec 15, 2005)

8.1 pints is 4.05 quarts according to http://www.sciencemadesimple.net/volume.php


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## 04gtolover (Feb 10, 2005)

dealernut said:


> Ok. So a 2.66 gear means what. What does the 2.66 mean exactly. I know it is a bit off topic, but damnit this stuff always drives me nuts.


2.66 is the number of times that the gear for first spins inside the trans :cheers mission to make the output shaft pin one time. The gear spins 2.66 revs and the outputshaft spins once.


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## Subdriver (Dec 28, 2004)

GTODEALER said:


> Sooooo, syncromesh fluid for our trannys may potentially be better than the ATF I'm running....... interesting. Subdriver, what do you think? :cheers
> *trying to stay on topic*


I'll respectfully disagree. Who says it is better? Royal Purple? Or someone who put some in and says it feels better (as many on this board have done)? Where is the technical data to support this belief? I haven't seen any.

The Tremec service manual states that the tranny in the GTO, same as the one in my Z06, requires a fluid meeting GM Dexron II/III standards (as does the car's owners manual which specifies Dexron III). I've spent quite a bit of time on the Royal Purple website and can find nowhere that it states that their Synchromax fluid meets GM Dexron III standards (though their ATF does). If your tranny fails and you have a fluid not meeting the owner's manual requirements in it, are you covered? Will Royal Purple cover it? I doubt it... 

AMSOIL makes a synchromesh fluid as well, the AMSOIL Synthetic Synchromesh Transmission Fluid (5w30). But again, this fluid is not labeled to meet GM Dexron III standards. 

Most synthetic ATFs are labeled to meet GM Dexron III standards. I use AMSOIL ATF in my Z06. My car has something like 16k total miles, 10 driver's education events, and about 28 SCCA races over a three year span and I'm still on my original, non-rebuilt tranny. I'm sticking with an ATF in my tranny. 

As for the comments about synthetic ATFs not being suitable for Tremec manual synchronizers, there is some truth to that, but it is dated. In the early years of the Corvette C5 line, the Tremec transmissions had paper based blocker rings. These rings did not perform well with ester based synthetics, such as Redline (AMSOIL uses a PAO base). I don't know what kind of base Royal Purple uses. Tremec changed the blocker rings years ago, and this issue doesn't really apply to newer Vettes, and I'm sure GTOs fall into the same category. :cheers


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## Steve A (Oct 28, 2005)

Gear ratio specs mean "to 1" although it may save space and not print it like that. So, for instance, a 2.97 ratio means 2.97 to one and that the engine/input shaft would turn 2.97 times for each revolution of the output shaft. The same theory applies to rear end (differential) ratios, a 4.56 to 1 means the input pinion shaft turns 4.56 times for each revolution of the output shafts (axles).

An overdrive ratio - .50 to 1 means that the engine/input shaft would turn once for each 2 turns of the output shaft/drive line.

So, for instance, the GTO with a .50 ratio in 6th and a 3.46 ring and pinion will have a final ratio of 1.73 and that is why it is pretty "soggy" feeling at low (or high) vehicle speeds.


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## ModBoss2 (Nov 13, 2005)

Subdriver said:


> I'll respectfully disagree. Who says it is better? Royal Purple? Or someone who put some in and says it feels better (as many on this board have done)? Where is the technical data to support this belief? I haven't seen any.
> 
> The Tremec service manual states that the tranny in the GTO, same as the one in my Z06, requires a fluid meeting GM Dexron II/III standards (as does the car's owners manual which specifies Dexron III). I've spent quite a bit of time on the Royal Purple website and can find nowhere that it states that their Synchromax fluid meets GM Dexron III standards (though their ATF does). If your tranny fails and you have a fluid not meeting the owner's manual requirements in it, are you covered? Will Royal Purple cover it? I doubt it...
> 
> ...


True, the RP Synchromax may not be stamped w/ GM's approval, but I feel that it will be completely safe, since it appears to be a true manual transmission fluid that's designed for manuals that were *originally filled with ATF and motor oil* from the factory. I just drained and refilled my trans with the RP Synchromax yesterday. Probably too early to tell yet, but I've already noticed that shifter operation is a little smoother.

And as far as warranty goes, the guy with the clipboard at the dealership is probably just as likely to wave his finger at me for that dated ATF synthetic info as he would be for the RP Synchromax not being Dexron III.


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