Honda MTF-3

[Honcho]

Does anyone know if the "white cap" Honda MTF is MTF-2 or MTF-3? I've seen conflicting statements on a google search. I ask because MTF-2 is a 20W, which is too thin for my tastes. Allegedly, MTF-3 is a thicker 30W, which is right where I want it.

Also, any feedback on Redline MTL? There are conflicting posts on this forum- some owners say it ruined their synchros and diff. Others have been running it for decades with no issues.

 

[Old Guy]

Does anyone know if the "white cap" Honda MTF is MTF-2 or MTF-3? I've seen conflicting statements on a google search. I ask because MTF-2 is a 20W, which is too thin for my tastes. Allegedly, MTF-3 is a thicker 30W, which is right where I want it.

Also, any feedback on Redline MTL? There are conflicting posts on this forum- some owners say it ruined their synchros and diff. Others have been running it for decades with no issues.

Can't comment on the viscosity of the MTF.

My last fill on the transmission I used 1/3 Red Line MTL and 2/3 Honda MTF. As far as I can tell there was no discernable difference in shifting; but, maybe my synchros are not far gone enough to benefit from the friction modifiers in Red Line. When I do the next flush next year it is just going to be Honda MTF (whatever weight came over the counter at the dealership). I have noticed that with my 6 speed, shifting doesn't get really smooth until the transmission has got really hot which means on days when it is 25 C or less I have to drive the car and then park it for 10-15 minutes to let the transmission heat soak. After that its slick as snot! If there is a 20W and a 30W version, 20W might be a better choice for me in terms of getting the box to shift nicely with less warm up.

I don't think Red Line can ruin synchronizers. I have been using 100% Red Line in various Euro cars for at least 25 years and the synchros have generally benefitted from its use. I don't think Red Line will damage an LSD either; but, it will alter / mess up its operation. In their product literature Red Line recommended against using Red Line MTL in transaxles where the oil will be shared with a clutch LSD. The friction modifiers in the oil alter the engagement of the clutches. There was a post from years ago where somebody had used 100% Red Line MTL in the transmission and was incurring premature / extended lock up of the differential on corners during a track event. Replacing the Red Line with conventional MTL restored normal LSD operation (may have required multiple flushes). The same problem would probably occur if you used the GM cocktail with 100% friction modified instead of the blend. Of course, if you don't go zooming around corners you may never know that your LSD clutches are not working exactly right.

 

[RYU]

This is a bit of a side note. I believe I will be the first one to install a Wavetrac LSD into my 6spd. Thanks [MENTION=9035]titaniumdave[/MENTION] for helping to bring this to market for our cars. The wavetrac is a torque sensing helical differential (no clutch packs) so i'll be using standard Honda MTF for the break in but curious also to try a synchromesh cocktail. HOWEVER, Wavetrac even recommends Honda MTF in their Wavetrac applications for the K Series guys. In inspecting the design of the Wavetrac it seems some friction modifiers would actually help it.

 

[Honcho]

Thanks guys- I've been WAY down the rabbit hole on this. Here are my takeaways:

• The NSX running gears are only partially submerged in trans fluid
• Trans fluid with synchro-friendly "friction modifiers" can cause the diff clutch to act more like an open diff, e.g., you lose or get "weird" LSD as [MENTION=26435]Old Guy[/MENTION] mentioned
• As such, you need fluid that flows well, but sticks to the running gears AND will not cause the clutch discs to slip too much
• The Honda MTF-2 (the white cap) is designed to meet the above standard, but it is a 20W that shears thinner under high heat and load (at the track)
• Most of the Japanese NSX experts use their own fluid blends to overcome the shear weakness of the OEM Honda stuff for customer cars that are used on the circuit Put simply, the fluids are full-synth (thus shear stable under heat) 30W or 40W that still meet the above specifications for flow, stickiness and diff
• Kaz recommended, rather than importing these fluids from Japan, just change the Honda MTF before and after each track day, which will give you enough protection

Taking all this into account, I was looking for a full-synth 30W trans fluid that meets all the criteria. Wouldn't you know that Honda MTF-3 is a 30W! But, it only appears to be available in the UK... I mean, I guess I can do a trans flush as part of my track day prep, but it would be a lot more convenient to just change it once per year and drive.

 

[Old Guy]

• Trans fluid with synchro-friendly "friction modifiers" can cause the diff clutch to act more like an open diff, e.g., you lose or get "weird" LSD as @Old Guy mentioned

Friction modifiers come in two forms. The friction modifiers in Red Line MTL and the GM friction modified 'effectively' increase the friction at the synchronizer contact face so that it does a better job of speed matching the gears. The similar effect on the LSD causes the clutches to engage faster or all the time giving you the equivalent of a closed differential. Presumably the Wavetrac and similar style differentials would not be affected by the modifiers.

GM and probably others sell (or used to sell) small bottles of friction modifier. It did exactly the opposite of what the Red Line friction modifiers do and was sold for use in specific LSDs on specific GM vehicles. Not the hot ticket for use with synchronizers. I recall forum posts with people applying liberal quantities of the GM friction modifier to transmissions with tired synchros and pretty much turning their gear box into a crash gear box.

Your observations about the weights of the Honda MTF are interesting. Just for confusion, I found references that described MTF (didn't specify which one) as a 10W-30 equivalent. In fact, the Honda Owner's manual for my 6 speed recommends that if MTF is unavailable that 10W30 or 10W40 SG (try and find SG these days) motor oil be used as a temporary replacement.

The UPC code for my MTL is 08798-9031 and the Honda spec that applies to that product code is MTF-7289. There is a Honda product called MTF-III ULTRA which is product code 08261-99964. Every reference to that product code and MTF-III shows it being sold in 4 l tins and originating in Japan and sold in Asia. There is also 08267-99901 called MTF 3 which appears to be sold in Europe in 1 l containers. I never found a Honda spec number for either of those. MTF Ultra III It 'might' be roughly the same product as MTF, just produced in Asian refineries rather than North American refineries. For what it is worth, if you search for various gear oils you will find that a lot of the 75W-80 GL4 gear oils claim that they are substitutes for both 08798-9031 and 08261-99964. Without access to the Honda standard that applies to MTF 3 and MTF III Ultra you have no way of knowing whether Honda has a different spec for those oils or whether they all have the same functional performance requirement (not the same as being the same oil) with just a name change for different markets.

Just for fun, I did a very dodgy, very subjective assessment of the MTF oil viscosity. I went out to our garage this AM and gave one of the 3 fresh bottles of MTF that I have sitting on the shelf a slosh test. The temperature dropped below 0C last night and our garage is detached and uninsulated. The oil in the bottle subjectively sloshed more like 10W30 motor oil, definitely not straight 30W which is starting to become viscous at 0C; but, could be straight 20W. Definitely lacking in quantitative measurement and definitely not definitive.

 

[Honcho]

[MENTION=26435]Old Guy[/MENTION] I just plugged the Honda MTF spec into the Google and it spit out a bunch of Honda Motorcycle fluid that meets the spec and is specifically designed for wet clutch type transmissions where the clutch and running gears share the same fluid. It's available in full synth 10W-30 and 10W-40. I wonder if this would also work in the NSX transmission?

Though, I think my best bet may be to just use the white cap and change it before and after a track day. I can't believe there is not a full synth 30W available in the U.S. that is suitable for wet clutch applications.

**EDIT**

Just found the below on GT-R Life from my GT-R ownership days. It's one of the Pentosin engineers explaining the FFL line of DCTF. It's full synth (heat shear stable), no synchromesh modifiers, designed to facilitate wet clutch engagement and will lubricate the running gears properly. Even though it is a DCTF, BMW just revised FFL-4 as service fill for its older manual transmissions, so it must be brass synchro safe too. I might try it...

in terms of performance our FFL-2 should be by far better than the original DCTF (double clutch transmission fluid) as our FFL-2 has been specifically developed to lubricate a DCT. From the small oil drain interval that Nissan prescribes we conclude that this oil seems to be an ATF. This is also what some tuners suspected who turned to us recently and asked for our oils as they were obviously not content with the quality / performance of the Nissan oil. We offered our FFL-4 to them as this is our second DCTF generation that we have developed for BMW. It is a real life time oil being used in the new BMW sports car M3. But if you have an easy access to the FFL-2 it is fine but I would replace it after 90.000 km...........

Before the first DCTF had been developed (FFL-2 for VW) the ATFs had the reputation to be the most difficult oils to be developed. The difficulty here is to find the best compromise of different requirements like e.g. to make the clutch work smoothly without causing shudder, to lubricate the gears without wear, protect the bearings, avoid foam,etc. Shudder is a bad noise. In the first place it is caused by an incompatibility of the friction of the oil and the clutch material. But the body of the car also plays an important role. The same engine and gear box in a BMW 3-series might be okay but awful in a car of a 5-series. Here the car itself as a swinging body comes into play. The clutch stands for the strings of a violine and the whole car reflects the body of the violine and represents the resonance body. This is the basis that needs to be understood when developing these oils.................

The most difficult task is to find the right chemistry for the clutch performance and the wear protection of the gears as these additives are of contradictional character. And when you switch from the ATFs to the DCTFs this formulation conflict increases exponentially as the level of the requirements for the wear protection climbs up into regions never seen before. Additionally as if all these requirements would not be severe enough our customers have asked for Life Time oils.

VW was on the verge of giving up their project because our competition (big multinational comp.) were not able to develop such a fluid. When they asked me in I had three months to fix it and I was successful. That was our first DCTF generation. The second is our FFL-3 for Porsche and FFL-4 for BMW. We are now working on a fuel economy DCTF that should save 1 to 2% of fuel. That is even more difficult as we have to lower the viscosities into a border line area risking wear.

I have been working in that area for 25 years by now. After every project I thought that we had reached the highest performance levels that could not be surpassed. I was always wrong. But I am sure that the big performance steps have been done.......

mit freundlichen Grüßen / kind regards
Dr. Edgar Steigerwald
F&E / R&D

 

[Old Guy]

That is interesting that you got those Google hits on the standard referencing use in motorcycles. I got nothing like that, just a bunch of hits for other 75W80 gear oils claiming compliance with the Honda standard. I was never able to find the actual standard. The motorcycle references are odd as engine oils can be substituted into gear boxes; but, purpose gear oils don't go into engines because they lack things like detergents unless those references were just to the final drive in shaft drive motorcycles. The modern 'motorcycle oil' standard is JASO-MA/MA1/MA2/MB (part of JASO T 903) which attempts to address some of the clutch + gears + engine issues. Be aware that the MA oils have friction increasers and the MB oils have friction decreasers. The MB oils are touted as high performance oils for motorcycles with the caveat that they may cause clutch operation problems (set out in Honda HP4M oil product info). Personally, if you are sticking with the NSX clutch style differential I would be inclined to stay away from these oils.

I found this graph of viscosity versus temperature for various weights of gear and motor oils. I don't know how old it is, whether it is just non synthetic oils and since I don't know the original source I can't really vouch for its accuracy. It also does not include single weight oils. What is interesting is that the weight of the oil appears to have minimal affect on the viscosity at higher temperatures.



I don't know enough about oil to know what that viscosity graph means in terms of lubrication performance. Does it mean that at higher operating temperatures a 75W80 versus a 75W90 gear oil is about the same and the primary determinant is cold weather performance. If that is the case, then by a rather tenuous extension, 10W versus 30W (or whatever 'weight' Honda MTF is if it is multi viscosity) might not be a material issue at elevated temperatures - if viscosity is the only consideration.

I think your 'stick with Honda MTF' is a safe plan.

 

[warrenw]

Like others, I personally use the Honda MTF that is sold at dealerships. It is the only one available at both Honda and Acura Canadian dealerships.
I have asked a question about MTF of a buddy that works at a Toyota dealership. He is their senior tech. His heritage is all Toyota. Big Supra guy.
He uses Honda MTF in both his manual Tacoma and his track Supra. He finds it provides a more consistent shift when the transmission is ice cold and track hot.
He also recommended Honda MTF for my wife’s Nissan manual SUV.
I tend to trust the manufacturers. Tough to out engineer a corporate engineer.


Sent from my iPhone using Tapatalk

 

[Honcho]

Like others, I personally use the Honda MTF that is sold at dealerships. It is the only one available at both Honda and Acura Canadian dealerships.
I have asked a question about MTF of a buddy that works at a Toyota dealership. He is their senior tech. His heritage is all Toyota. Big Supra guy.
He uses Honda MTF in both his manual Tacoma and his track Supra. He finds it provides a more consistent shift when the transmission is ice cold and track hot.
He also recommended Honda MTF for my wife’s Nissan manual SUV.
I tend to trust the manufacturers. Tough to out engineer a corporate engineer.


Sent from my iPhone using Tapatalk

Thanks Warren, that is good data. For a street driven NSX, I think the consensus is that that OEM MTF is the best option. I had nothing but good experience with the white cap MTF on my 91, including at the track (though I did not inspect the diff/synchros after track days). The concern now is that I'm building my S Zero to be driven HARD and on the track. The advice from the NSX experts in Japan and Kaz is that the OEM fluid is a thin mineral oil (very close to an ATF in fact) and not up to the task of prolonged high-temperature operation. The inference I draw from that is that I will cause excessive wear if I do not run fresh fluid in the box. Thus, Kaz's advice to change it before and after a track day. The Japan-based shops (T3TEC, RFY, Advance, Route KS, J's Racing, etc.) run their own full-synth blends to get around this problem for customer track cars. You can just fill and drive. Unfortunately, we don't have access to them.

I ordered 3L of the Pentosin FFL4. I'm going to run the Honda fluid for a 500ish mile break-in and than swap with the Pentosin. The FFL4 is a lifetime fill fluid for DCT applications, but since the NSX does not have the same filter as a DCT, I plan to just change annually with my engine oil. I'll do a UOA on the first change to check for any problems. Of course, if it runs like garbage, I'll swap back to the Honda stuff and resign myself to two trans oil changes for every track day....:frown:

 

[Old Guy]

I read with interest your note on the fluids for DCts, in part because I have an Audi with the DL-382 7 speed DCT. In the DL-382 which is used in the Audi Quattro Ultra system, Audi is using two separate fluids in the transmission. They have one fluid for the hydraulic controls (mechatronics in Audi-speak) which does the shifting, operates the two clutches and also cools the two clutches. They have a separate fluid for gear lubrication. What is interesting is that the service intervals call out a higher change interval for the hydraulic control fluid than the 'gear' fluid (the gear fluid appears to be a lifetime service interval; but, there is provision to change it). I am guessing that this might be due to the fact that clutch operation results in a lot of heating plus shear. Audi may have migrated to this dual fluid system to address the separate lubricating requirements for the clutch / hydraulics and the gears.

If the Nissan / BMW DCTs are single fluid systems the oils designed for those boxes (FFL4) may be optimized compromises. They may not be an optimized fluid for a gearbox which does not have to deal with hydraulics and a lot of clutch operation. While FFL4 may be a better DT lubricant, it might not be better than a purpose gear lubricant.

 

[Honcho]

I read with interest your note on the fluids for DCts, in part because I have an Audi with the DL-382 7 speed DCT. In the DL-382 which is used in the Audi Quattro Ultra system, Audi is using two separate fluids in the transmission. They have one fluid for the hydraulic controls (mechatronics in Audi-speak) which does the shifting, operates the two clutches and also cools the two clutches. They have a separate fluid for gear lubrication. What is interesting is that the service intervals call out a higher change interval for the hydraulic control fluid than the 'gear' fluid (the gear fluid appears to be a lifetime service interval; but, there is provision to change it). I am guessing that this might be due to the fact that clutch operation results in a lot of heating plus shear. Audi may have migrated to this dual fluid system to address the separate lubricating requirements for the clutch / hydraulics and the gears.

If the Nissan / BMW DCTs are single fluid systems the oils designed for those boxes (FFL4) may be optimized compromises. They may not be an optimized fluid for a gearbox which does not have to deal with hydraulics and a lot of clutch operation. While FFL4 may be a better DT lubricant, it might not be better than a purpose gear lubricant.

What drew me to the FFL4 is that the BMW DCT boxes share fluid between the clutches and the running gears/bearings. BMW recently replaced the Pentosin MTF-2 with FFL4 as service fill for their manual transmission applications, including all ZF series 5 and 6 speeds. Apparently, the FFL4 provides sufficient lubrication and anti-wear properties for the gears, synchros and bearings. Since it is also wet clutch friendly, it should work well in the NSX differential. It's also yellow metal safe, per the below:

https://www.youtube.com/watch?v=7u1N16GMwzk

**EDIT**
If the FFL4 works well, it's possible less expensive full synth options like the Valvoline DCT may work as well, as long as they meet the applicable BMW specification.