Moly in ATF - Why Not?

[Titanium_Alloy]

Hi guys,

I've researched a few used oil analysis and VOAs on different ATF fluids and it seems like none of them contains molybdenum.

I was thinking: wouldn't an automatic transmission be a perfect candidate for using molybdenum (I guess in form of MoS2)? High pressure, high shear zones, high temperature clutches and valves, and long drain intervals in modern transmissions would probably benefit from a sizeable amount of molybdenum (I suppose somewhere in range of 200-600 ppm, but that's just an assumption).

Molybdenum could provide great surface coating, thus preventing or at least reducing metal to metal contact under high pressure. It probably would also reduce famous metal shavings we can see on the pan magnets.

So the question is: why ATF manufacturers don't use it?

Maybe Redline, who is famous for high molybdenum amounts in their products, would have some molybdenum in their ATFs but I wasn't able to find any VOA or UOA to support this claim. I'm inclined to think that if no one has it, Redline ATF probably would not contain any molybdenum as well.

Or is it clutches which are made of special material which varies from one transmission maker to another would result in some kind of problematic shifting if coated or contacted with molybdenum?

What are your thoughts on that?

Regards,

 

[Lahj Bawls]

Just as a suspicion I doubt that MoS2 in higher concentrations is suitable for longer drain intervals. In fact, I won't keep such a supplement in longer than 3000 Mi (50/50 city/hwy) in an engine until somebody can kill my suspicion. So the really long ATF drain intervals would be one problem IMO.

But the primary problem, like you said, is the wet clutches:

quote:

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Or is it clutches which are made of special material which varies from one transmission maker to another would result in some kind of problematic shifting if coated or contacted with molybdenum?

---

Now (being a big big Moly fan

), I recently ordered Mr Moly/Molyslip ATF, Gear, and Engine supplements. The ATF supplement version does not contain MoS2 and there is a warning on the MTF and Engine Molyslip to not apply this to anything with wetclutches because of the MoS2. The ATF Molyslip contains another form of Molybdenum, I think it's just the pure form of the Mo metal. This supplement is really thick and looks a little like STP engine treatment, probably thicker though.

I don't know how good of a lubricant pure micron sized clumps of Mo would be, but clearly not as slippery as MoS2 in order not to interfere with the clutches. I don't know if this form of Mo is any better than say Zinc for antiwear. I assume zinc is already in all the ATFs.

Seems to be shifting really nice (noticably smoother and better than before) after I mixed a full tube of Molyslip ATF + 1 bottle of Gunk ATF conditioner along with 4 qts of fresh Castrol ATF into the 11 qt capacity GM transmission.

So far so good

! Seems like I'll keep being a moly fan!!

 

[Titanium_Alloy]

I personally wouldn't add molybdenum additive to my ATF. The only thing I added in one of our cars was LubeGard, which has a good reputation and has been approved by some car manufacturers.
I have LubroMoly MoS2 engine protect in the same car, but honestly I see no difference. This is the last time I added anything to my engine or transmission except approved ATF and motor oil. Seems like a big waste of money, which hopefully does not harm engine/ATF.

I would want to see though ATF manufacturers (like in motor oils) mixing in some molybdenum in ATFs, if of course they find it reasonable.

Regards,

 

[MolaKule]

None of the ATF producers use moly in their formulations; this includes Schaeffer's, Mobil 1, Amsoil, B&M, etc.

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=11;t=000086

We have to remember there are two forms of moly; the moly disulfide powder, and the synthesized organometallic MoDTC.

The moly disulfide powder is used in gear oils to act as Extreme Pressure additives to coat the gears. The synthesized organometallic moly, or MoDTC, is used as Friction Modifier and as an antioxidant in motor oils and hydraulic oils. You don't want these moly particles coating organic clutch material.


For ATF's, there are better synthethsized organic friction modifiers than MoTDC's, and they do not coat clutch faces with metals. In addition, these friction modifiers can be fine tuned to the transmission's materials and shift transitions. These new friction modifiers leave only a one-molecule thick layer on the clutch material.


Added after first Submission:

You will also notice the very low zinc levels in the VOA's for the same reason stated above. These ZDDP additives are special low zinc, high phosphorus additives.

[ December 04, 2003, 03:35 PM: Message edited by: MolaKule ]

 

[Ken2]

quote:

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Originally posted by Titanium_Alloy:
Or is it clutches which are made of special material which varies from one transmission maker to another would result in some kind of problematic shifting if coated or contacted with molybdenum?

---

Yes.

We don't know what's really in the Mr. Moly stuff, so we don't know what it's doing. In any case, I'd prefer cleaning a transmission with Auto-Rx and doing a complete ATF flush rather than adding additives and supplements, with the possible consideration of Lubegard.


Ken

 

[Titanium_Alloy]

quote:

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Originally posted by MolaKule:
You will also notice the very low zinc levels in the VOA's for the same reason stated above. These ZDDP additives are special low zinc, high phosphorus additives.

---

Hi MoleKule,

As I'm aware International Lubricants, the maker of LubeGard, indicates that Dexron III must not contain any zinc (at least factory reference fluid doesn’t). Which is pretty much confirmed by Mobil 1 ATF used oil analysis indicating that sample contains 8-30 ppm of zinc - seems like miniscule amount to affect any ATF properties.

On the other hand UOA sample of Redline C+ ATF at: http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000505#000000

contained 361ppm of zinc, which is like 20-30 times more compared to Mobil's Dexron III.

Is it the difference in formulations between Dexron III and C+, or it's more a brand difference between Redline and Mobil?

I was wondering if you know the level of zinc in Redline's D4 ATF.

Thank you,

 

[MolaKule]

In the link you refer to, we do not know the VOA and the additve package of the virgin fluid since JB added some kind of unknown additive, and the additive itself had not been analyzed prior to mixing it with the fluid he already had in it, so don't take that one analysis as accurate or indicative of that fluid. In other words, too many unknowns for that sample.

The level of zinc in D4 is usually less than 5 ppm. Most ATF fluids have a zinc level less than 10 ppm.

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=11;t=000086#000000

Most of the friction modifiers in ATF's are now non-metallic and organic, so they won't show up in a VOA/UOA.