Firebrian

http://www.mustangandfords.com/how-t...n-maintenance/

An interesting article on Tremec transmission synchronizers. This article talks about the T-5 but is applicable to all versions using organic fibrous clutch material lining bonded to the friction rings of the synchronizer assemblies. Manual transmission lubes that will improve anti-wear capabilities on the gears, might also cause problems with synchronizers that could shorten overall transmission life.

The following is an excerpt from an article concerning all T5 World Class (WC) trannys used in Mustangs since 1985, from the May 1992 issue of Car Craft magazine written by M. Davis and titled "World Class Act":

"The new synchros are the most significant upgrade. WC 3-4 synchronizers are sintered metal blocking rings that, under high shift force, won't distort as easily as the old brass rings (used in non-WC T5's). The WC T5 blocking rings also employ an organic lining on the inner cone surface that mates with the speed gear's cone surface. This lining acts like that of automatic transmission clutch plates, and offers the advantage of more consistent long-term performance, as they suffer less degradation over time. Dexron II automatic trans fluid must be used as a lubricant in T5 WC transmissions because it does not attack the adhesive that holds the organic lining to the blocking rings. Traditional manual trans gear lubricants containing "EP" additives will attack these linings and must not be used.".

dailydriver

Maybe we should forward the above to MolaKule on bitog?

Firebrian

That thought did occur to me. But, I don't it will change his mind any considering the interstitial swell in those linings is almost miniscule per his calculations. In his latest posting he states that the current ATF's have very minimal to zero EP additives, some of which ruin synchronizer friction rings. I'm in the process of reviewing the entire spectrum on satisfactory manual transmission fluids for the T56 with cellulose lined synchronizer friction rings. It's much the same thing I did 4 years ago when I last changed the fluid, only 5K miles ago. And at that time I decided to go the safest route possible with plain old conventional DEX III ATF.

I'm not ready to take the leap to a 9-10 viscosity synchromesh and I am still leery of all synthetics, even Mobil 1 syn ATF, Amsoil ATF/ATF ATD, and Redline ATF D4. Right now I'm considering the same old Valvoline ATF I used last time, regardless of the weaker add packs. I know ATF shears down pretty fast so changing it every 5K miles/4yrs should compensate. But it makes you wonder how so many of these T56's went 100K-150K miles or more on the factory ATF fill. In MolaKule's ATF white paper the additive packs for the early DEX III's were quite stout having levels of Phos and Sulfur probably 2X that of today's generic ATF's.

The Pennzoil and Mobil multi-vehicle synblend ATF's look to me to be better than the Valvoline DEX III. Valvoline Max Life ATF has a stronger add pack than these other DEX III's...but the viscosity is only 6.0 which is too low imo. I'm looking to stay in the DEX III range of 7.0-8.0. GM MTL for manual transmissions and xfer cases (88861800) is another option as that's specifically still recommended by GM for the T56. VOA's of Amsoil's Torque Drive ATF and GM MTL showed them to be somewhat similar in viscosity and levels of Phos, Calcium, and Boron. I read one thread where a Vette owner sent in a sample of the GM MTL to Royal Purple for analysis. The reply back was that it was similar to standard ATF's....though no numbers were provided. Per Molakule, they state the GM MTL is similar to the conventional name brand ATF's but with slightly stronger anti-wear package (ie phos/boron). The synthetic ATF's have the strongest add packs among the various ATF's.

I'm more interested in making the synchronizers last and at the same time perform properly and rapidly. I think they are more limiting than the gears/bearings themselves for nothing more than street driving. I read one guy's experience with a 2008 Vette running an ATF - that sheared down from 7.5 to 5.8 cSt in only 8,000 miles. The RedLine D4 ATF will not shear down below around 6.4 cSt.

Still researching and coming up with some good information, but little in the way finding the "Holy Grail" answer as to what is the "best" fluid. The best fluid seems to vary for each manufacturer, each model car/trans, and potentially every individual transmission build. At least that's my take from reading thousands of posts on the subject. My T56 has clutch friction surfaces similar to what's found in an automatic transmission. The gears should require manual transmission lubricant. So how can you meet both specs? Update: for my current trans fluid change I went with the GM MTL 88861800.

https://shiftsst.com/blog/216-transmission-fluid

Fluid recommendation from a Tremec dealer.

http://www.tremec.com/menu.php?m=110

Tremec frequently asked questions about manual transmissions.

http://www.flaglercountycorvetteclub...%20Article.pdf

Different fluids for different materials.

https://www.bobistheoilguy.com/forum...Number=1613902

Bitog thread showing 2009 VOAs for M1 ATF, Redline D4, and GM MTL and Xfer case fluid.

http://www.c66racing-synthetics.com/...%206-10-07.htm

Here's a Blackstone UOA from June 2007 on a young T56 using regular Dex 3 ATF. In 10,600 miles of simple daily driving the fluid was spent Add pack is not all that robust. Conventional factory fill ATF sheared down from 7.5 to 5.0 cSt in only 10,600 miles. The Amsoil ATF was still at 6.85 after approx 6K miles...after starting out at the same level. More proof that conventional stuff should be changed out probably every 4K-6K miles. Amsoil has since recommended their ATF ATD which starts out at 7.6 cSt.

http://www.c66racing-synthetics.com/...sion%20UOA.htm

Rockland Standard Gear has some articles on T56 transmission lubricants and manual lubes in general. they recommend ATF for T5/45/56's.

http://tcase.rsgear.com/articles/2003_10.pdf

http://tcase.rsgear.com/articles/2000_08.pdf

http://www.ls1gto.com/forums/showpos...7&postcount=11....failure info on early T56's with paper blockers.

Differences in the Amsoil trans lubes.

http://www.cadillacforums.com/forums.../t-263028.html

Article showing typical shear rates for ATF's.

http://www.allpar.com/mopar/transmissions/fluids.html

LS1 GTO site discussing fluids for T56's. Surprised that members reported issues with several well thought of synthetics and even some conventional ATF brands. Goes to show that no two cars are the same and may not behave the same on the identical fluids. In this case the GM Manual Trans Fluid came out well regarded without issues. While GM fluid MTF shears down faster than synthetics, you can just change it twice as often....it's cheap enough.

http://www.ls1gto.com/forums/archive.../t-732201.html