emg88

I'm with Dean! Amsoil Synchromesh Manual Trans Fluid, Severe Gear for the diff. and the European Spec Oil! All get the BIG

The Amsoil Trans Fluid shifts fantastic when warm and it holds up with no degradation. It's a little slow on the synchros when cold, but then so am I!

S1997

^^^Thanks, Ed!

Yeah, my one year membership is running out soon, so I think I'll order some stuff in quantity before it does. I'll include an order for some of the MTF. Actually, the wholesale membership is quite cheap to renew, though. They send you all this heavy literature trying to get you to become an Amsoil mini-dealer -- something I wouldn't be good at.

BTW, Dean, the package arrived. I hope I am smart enough to install it. I may have to be in touch with Dr. C for advice and help. My initial cursory perusal of the instruction sheet didn't result in permanent enlightenment about the matter. Apparently it's Germans trying to explain the instructions in intelligible English ...

dlq04

I have rebuilt a few manual transmissions in my day but when it comes to fluids, all I can swear to is they leak out of British cars and stay in Japanese cars.

dean

I hope you're smart enough too. There's no sending it back for a refund. I've already squandered the money on strippers and beer.

Legal Bill

No, it isn't. The teeth engage the syncro, then the synchro pushes against, and spins the gear. If the synchro engaged both the drive gear and the shaft with teeth it would wear out very quickly and break. Synchros are skinny little things. As I understand it, GM-FM is "Friction Modified" to reduce its lubrocity (not sure that is a word) in certain situations.

This really isn't an argument. This what I have been told by people like Road Rage who is a tribiologist. I'll see if I can find a link to his prior posts in under the hood.

Edit.

I couldn't find the comments I am thinking about, but here is a thread where the issue is discussed by Road Rage in a fashion that assumes the participants are familiar with the issue of lubricity, shear and how a fluid that is too "slippery" will not work well.

raymo19

OK - as long as it's not an argument. Where's the link?

raymo19

Yes it is.

It works like this:

"If the teeth, the so-called dog teeth, make contact with the gear, but the two parts are spinning at different speeds, the teeth will fail to engage and a loud grinding sound will be heard as they clatter together. For this reason, a modern dog clutch in an automobile has a synchronizer mechanism or synchromesh, where before the teeth can engage, a cone clutch is engaged which brings the selector and gear to the same speed. Moreover, until synchronization occurs, the teeth are prevented from making contact, because further motion of the selector is prevented by a blocker (or "baulk") ring. When synchronization occurs, friction on the blocker ring is relieved and it twists slightly, bringing into alignment certain grooves and notches that allow further passage of the selector which brings the teeth together. Of course, the exact design of the synchronizer varies from manufacturer to manufacturer.

The synchronizer has to change the momentum of the entire input shaft and clutch disk. Additionally, it can be abused by exposure to the momentum and power of the engine itself, which is what happens when attempts are made to select a gear without fully disengaging the clutch. This causes extra wear on the rings and sleeves, reducing their service life. When an experimenting driver tries to "match the revs" on a synchronized transmission and force it into gear without using the clutch, it is actually the synchronizer that makes up for any discrepancy in RPM, deceiving the driver into an exaggerated sense of how much human skill was involved."

Clearly the synchronizer synchronizes the process and that's all it does (albeit a very important job). It has no role beyond that. The teeth mesh, the gears mesh, and away you go.

I really don't think anyone would produce and market a manual transmission fluid that was too slippery for the application.

When owners complain about a cold start 1-2 grind or notchiness is it because the tranny fluid is too slippery? Of course not. It's because the metals are contracted and the fluid is not at its operating viscosity.

That's why the friction modifiers (like molybdenum) and their polar molecules riding the boundary layer between the metal parts mitigate the lack of lubricity.

S1997

Am I gonna have to report this to Martha? Strippers and beer? Now THAT'S lubricity!! Damned Floridians!! Hanging Chad Men's Club? Now the teeth engage the gears ... n' ...

Legal Bill

Sorry. Right here:

https://www.s2ki.com/forums/index.ph...pic=193838&hl=

Skim through and read Road Rage's posts and you will see the comments about fluid having too much lubricity.

dlq04

It's my understanding that baseball cards in the spokes transformed any bike into a motorcycle, so does that make them "lubricity".