moly in manual transmission fluid?

[MolaKule]

"One of the reasons not to use moly in an MT is that it competes with the chemistry of the special synchro friction modifier."

I would not put moly in a light truck or car manual transmission.

The above quote is from personal experience with many formulations for manual transmissions.

I would say that that anyone who puts any third party additive in a formulated, dedicated manual transmission fluid is asking for trouble in the long term.

 

[GMorg]

Do the same reservations come into play for transfer cases and open differentials? In the absence of a need for the synchro friction modifier(s), I am struggling to find a downside other than sedimentation.

 

[dailydriver]

Originally Posted By: deeavi
I have used Moly with Amsoil ATF in my Tremec T56 for 4 years. My car has 500 rwhp. This is a street car, not a drag car, but I take it down the 1/4 mile once or twice a year. Never have had a problem. I always wait for the fluid to get up to operating temps before shifting it hard. I was concerned that I needed more torque handling capability, and recently had it torn down for a 31 spline main shaft upgrade. The transmission mechanic said that it looked great inside. Hardly any wear at all. We did a full rebuild anyway. I have never put slicks on the car, but I do run drag radials to keep it civil under power. Just my vote for Moly! I believe in it.


Just don't put any in your 12 bolt/9/S60/whatever, especially if you have a clutch type limited slip.
Spool, OK, locker maybe Most on here would NOT add any to a worm gear/Torsen type diff either.

 

[GMorg]

Excluding the Torsen T-2R RaceMaster which has clutches, what would be the issue with MoS2 in a Torsen/Gleason differential? Are these differentials friction dependent?

 

[dailydriver]

Originally Posted By: GMorg
Excluding the Torsen T-2R RaceMaster which has clutches, what would be the issue with MoS2 in a Torsen/Gleason differential? Are these differentials friction dependent?


I've never looked at the explosion of a T2R. I was always wondering how they gave it more bias/preload than a stock/street/standard T2, now I know. Thanks.

The Eaton techs claim that for their True Trac diff (a Torsen/Gleason worm gear 'type') there needs to be a good deal of friction between the outer worm/roller gears and the case in order for it to work/bias properly (also why they claim one should not use synthetic gear oils in this diff).

That being said, there are MANY on here who think that what the Eaton techs say/suggest is not worth the air they use to speak those suggestions.

 

[mechtech2]

New Honda break in oil has fairly high moly.
Regular off the shelf Honda oil may have some, but not as much.

A little moly can be overcome, but it was never best or appropriate.

 

[Gearhead]

Originally Posted By: mechtech2
I would love to use moly in manual trannys! I have in the past.

It would be great for all sorts of things, EXCEPT the very important actual contact of the synchro faces.
You might get lucky with aggressive synchros, but it's not worth it if things go bad.
How can we tell in advance? We can't! And the moly is very tough to remove all the way. Take it apart and grind it off!?


This is a timely thread & post, Thanks! I don't want to risk making my tranny harder to engage than it is currently. I'll stick to molly in the engine oil only.

Before adding any additives, I would consult with the my OEM.