DIY – USE LOW Friction Modified ATF to DECREASE CLUTCH WEAR - AcuraZine - Acura Enthusiast Community

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Old 10-05-2012, 10:49 PM
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A lower FM (friction modified) ATF will decrease transmission clutch wear, and allow a faster (quicker) shift, without causing a harsh shift. The following discusses how to adjust the level of FM in your ATF by adjusting the amount (percentage) of TYPE-F ATF used in your transmission.

TYPE-F ATF contains zero FM.

For longer life of my own RDX transmission, I want to reduce the wear on the transmission shift-clutches, by reducing the FM in the ATF. The more FM (friction modifier) in the ATF, the more slip occurs during a transmission shift. This increases wear of the trans clutches.

If you wish to discuss this subject, here are some threads:
Very interesting conversation with my transmission builder on the TL

Racing ATF – see post #842 and #976 in particular
[my ed: Red Line brand TYPE-F is labeled RACING ATF on the bottle]

High FM is used to produce a smooooth but loooong (lazy) shift. A high FM-type ATF just causes unnecessary slipping while shifting, and more clutch wear. With electronic control, there is no reason why a modern automatic-transmission cannot shift quickly and smoothly, without harshness, while using a low FM-type ATF.

If you have ever driven a manual transmission, you know that minimal clutch slipping during manual transmission shifting can be achieved without causing a jerking/ harsh shift. And also, that undue manual clutch slipping or failure to reduce engine power during shifting, will quickly wear out the clutch.

A low FM-type ATF can work on the RDX because the DBW (drive-by-wire) system cuts engine power during the shift, controlling any shift-harshness (jerking) caused by a quicker shift. The electronics in the RDX transmission controls the actual time-length of the shift, based on the amount of clutch slip – lower FM, less slip, quicker shift.

The 1990s Honda Accord and Civic transmissions typically had long lives, if reasonable maintenance was performed (ATF and filter changes). Current Acura RDX, MDX, and TL models have a lot more horsepower, and weight a lot more, than those older Honda model cars. That means more stress on the transmissions. And current model Honda/ Acura’s have no replaceable transmission filter.

Beginning around the year 2000, Honda suffered multiple class-action law-suits concerning failing transmissions in Odyssey, CL, TL, and MDX models. It was the clutches that failed, never the hard-parts (gears). Current Honda transmissions seem more reliable, but I do not think that there is yet enough long-term data to say that the current Honda/ Acura 5-AT transmissions will last 200K miles, by following the maintenance schedule of the OM (owner’s manual) and MID (maintenance indicator display).

Honda is not the only manufacturer to suffer class-action law-suits over transmission failures. All of the car manufacturers have been trying to decrease cost-of-ownership, at least for the first owner, by decreasing maintenance costs. Transmission replaceable filters are a thing of the past, in many vehicles.

Transmission ATF OCI (oil change intervals) have been doubled, tripled, or even quadrupled in the past 10 years. Car makers now require synthetic ATF for most vehicles, GM requires synthetic ATF for ALL its current transmissions (Dexron-VI). But do you really think Honda (or any other car maker) cares if your current vehicle transmission lasts for 200K miles? Or is their only interest that it last for the length of the warranty?

Honda ATF, whether Z1 or DW-1, has a higher FM level than Dexron-III, which was listed in earlier model Acura Owner Manuals (OM) as an alternative ATF. Dex-III is no longer licensed by GM, which is probably why Acura OMs no longer list Dex-III ATF as an acceptable alternative.

I have used 87% Red Line brand D4 ATF in my RDX, which is a Dexron-III type and Honda Z1 compatible ATF. D4 contains less FM than Honda ATF, but I did not notice any difference in shift quality from the OEM Honda ATF. All Red Line ATF types are ester-based synthetics, rated with GL-4 gear protection.

I have used the following percentages of Type-F ATF, mixed with an FM-type ATF: 35%, 50%, 62%, and 87%.

More than 67% Type-F is NOT suggested for use in your RDX, although I have used an 87% mix. That was 7-qts of Type-F and 1-qt of Honda Z1. I did not find the shifts to be unduly harsh or ‘jerky’, even down to zero degrees Fahrenheit. But after about 4K miles there was some ‘unevenness’ in the shifting. I assume that the FM in the one remaining quart of Z1 had worn out. So some level of FM in the ATF is required for the RDX transmission to function properly.

You can read more here:
The Optimal Percentage of Racing ATF [ed: is 65%]
[my ed: Red Line brand TYPE-F is labeled RACING ATF on the bottle]

The 50% Type-F mix produces a shift that in my opinion is ‘better’ than the OEM Honda ATF. The shift is slightly quicker and does not seem as lazy as the Honda ATF. To me, it seems smoother than the OEM ATF shift.

The 62% Type-F mix produces a quick but not harsh shift. This is the optimal compromise between minimal clutch wear, and an overly firm shift feel. During the winter, the first couple of shifts are rather firm, and you may not like that. But after a couple of miles, the shifts are acceptable. And the more throttle used, the faster the shift, without being overly firm and certainly not harsh.

The 65% Type-F optimal mix suggested in the link above, is not practical for the RDX. The TL transmission, which is discussed in the OPTIMAL PERCENTAGE ATF link above, has a different total volume in quarts vs. the RDX transmission. The 62% mix is very easy to achieve for the RDX transmission, without resorting to measuring small parts of a quart.

If you try the Type-F fluid and do not like the shift feeling, you can always simply replace some (or all) of the Type-F with a FM-type fluid.

Type-F ATF was originally specified for FORD automatic transmissions until about 30 years ago. Type-F ATF contains zero FM (friction modifiers). Type-F ATF is available in both synthetic and mineral-based formulations. Anyway, there are a number of different brand Type-F fluids available from your local auto parts store. Type-F is currently used mainly in drag racing cars, to produce the maximum clutch lockup with minimal slip (quickest-shift). That is the reason why Red Line labels their Type-F oil as a ‘racing’ oil.

But my only personal experience, is with Red Line brand Type-F ATF. If you wish to use another brand of Type-F ATF, read one of the links that I have listed above. Other people have used other brands of Type-F ATF, and posted their comments.

1x4 = 2-qts of RL Racing, 2-qts of RL LW
1x4 = 1-qt RL Racing, 1-qt RL LW, 2-qts RL D4
1x4 = 1-qt RL Racing, 1-qt RL LW, 2-qts RL D4

Assuming that you have 100% Honda ATF in your transmission, then perform the above ATF drain-and-fill changes. If the transmission is hot/ warm, then you will drain approximately 4-quarts. Depending upon the ambient temperature, I usually drain 3-qts 28oz to 4-qts 3oz. The RDX transmission contains 8.2-quarts total, according to the FSM (factory service manual). Only 4-quarts (nominal) can be drained each time.

NOTE: the 0.2 quarts part of the total 8.2 quarts RDX trans volume is ignored in this post. That is only 6.4 ounces, which is not really relevant out of 8 quarts total. Besides, I have noticed that the volumes in the FSM (factory service manual) are not always very accurate to the nearest ounce anyway. You can verify this for yourself, by doing your own conversion between the QUART and LITER dual amounts listed for each liquid volume. My actual conversions never match those in the FSM. The FSM is just rounding off to the nearest amount.

So a 1x4 means one drain-and-fill of 4-qts nominal.
RL Racing = Red Line Type-F Racing Synthetic ATF, p/n 30304
RL LW = Red Line Type-F Light Weight Racing Synthetic ATF, p/n 30314
RL D4 = Red Line D4 synthetic ATF, which is Honda Z1/ Dex-III compliant, p/n 30504

RL Racing and RL LW are mixed together, because they have two different viscosities, which are different from Honda ATF. Mixing RL Racing and RL LW will give a viscosity similar to the Honda ATF fluid. If you drain slightly less or more than 4-quarts, then make the adjustment during the refill with the D4, using either slightly less or more than one full quart.

Maintenance is to continue with the same 1x4 drain/fill as the last one in the table above. With each additional 1x4, the ATF mix will slowly approach an actual 50% Type-F and 50% D4. There will always be some small amount of old ATF remaining even after a 3x4 (3 drain/fills of 4-qts), because only 4-quarts out of 8-quarts total can be drained at one time.

After a 3x4 the RDX transmission will contain 50% Type-F and approximately 50% FM-type ATF (the D4). The actual fill will be 2-qts of RL Type-F Racing, 2-qts of RL Type-F LW, 3-qts of RL FM-D4, and 1-qt of whatever was originally in the transmission, which was presumably Honda ATF.

How often should you now update or drain the ATF? I personally do a single drain/ fill once each year, depending upon miles driven. Red Line ATF is supposed to be an extended drain type ATF. It will last (at least) as long as the Honda stuff. And Honda ATF is supposed to last for a minimum of the first 60K miles, even under severe driving conditions (2009 RDX OM).

1x4 = 2-qts of RL Racing, 2-qts of RL LW
1x4 = 2-qt RL Racing, 1-qt RL LW, 1-qts RL D4
1x4 = 1.5-qt RL Racing, 1-qt RL LW, 1.5-qts RL D4

The above will produce a 62.5% level of Type-F ATF, that is, 5 quarts of Type-F and 3-quarts of FM ATF. The Type-F percentage will be a mix of 3-quarts of RL Racing and 2-quarts of RL LW. And if you want to use a different mix than 50% or 62% of Type-F, then you will need to figure out how to mix it yourself.

After the 3x4 the transmission will contain 3-qts of Racing, 2-qts of LW, 2-qts of D4, and 1-qt of whatever was originally in the trans when you started. The last 1x4 can be used as the maintenance drain-and-fill, to retain the same 62.5% Type-F ATF.

In the following table, the GREEN numbers are officially published by the various manufacturers – all other (BLACK) numbers are computed values.

120C/ 100C/ ..40C/ .0C/ -20C -40C .... cSt at Centigrade temp/ Brookfield cP @-40C
..../10.00/ 53.70/ 405/ 1868/ 15,000 = RedLine Synthetic Racing 100% p/n 30304
5.52/ 7.70/ 34.00/ 196/ .728/ ...... = GM OEM Dexron III-H (Petro-Canada)
..../ 7.50/ 38.00/ 276/ 1269/ ...... = RedLine Racing 61.0%/ LW 39.0% (Synthetic)
5.36/ 7.50/ 34.00/ 205/ .798/ .5,200 = RedLine D4 (for Honda ATF-Z1) (Synthetic)
5.22/ 7.40/ 36.30/ 251/ 1100/ 10,040 = Mobil-1 Synthetic, Dexron III-H/ Mercon
..../ 7.20/ 36.00/ .../ ..../ ...... = Castrol Dexron III-H (when it was licensed)
5.12/ 7.06/ 29.49/ 158/ .553/ ...... = Honda OEM ATF-Z1 (discontinued)
..../ 7.00/ 37.00/ 294/ 1477/ ...... = Penrite HDPS (semi-Synthetic for Honda DPSF)
4.87/ 6.93/ 34.87/ 255/ 1187/ 11,250 = RedLine Racing 50%/ LW 50% (Synthetic)
5.07/ 6.83/ 25.09/ 110/ .327/ ...... = Honda OEM DW-1 (Idemitsu Lubricants America)
4.50/ 6.40/ 30.70/ 210/ .931/ .4,500 = RedLine D6 (for GM Dexron-VI) (Synthetic)
..../ 6.00/ 29.80/ .../ ..../ ...... = GM OEM Dexron-VI (Petro-Canada)
4.25/ 6.00/ 29.50/ 214/ 1006/ 12,500 = Valvoline licensed GM Dexron-VI (Synthetic)
3.50/ 4.90/ 23.20/ 165/ .781/ .7,500 = RedLine LW 100% (Synthetic) p/n 30314

NOTE 1: the computed viscosities, were computed using the following web site. I do not know just how accurate the web-site computations may be. Do be aware that the accuracy of the above computed values depends upon the number of decimal digits used, to make the computations. The web site below has various computation tables, and the number of decimal digits used in the computations, depends upon which table is used to make the computation. This can make a difference of 2 or 3 percent in the computed values.

NOTE 2: the 61% mixture of Red Line Racing ATF, is simply to provide a viscosity of 7.50 cSt at 100C degrees, for the sake of comparison with the other ATFs in the table, Red Line D4 in particular.

NOTE 3: Dexron VI requires a different approach, compared to conventional ATF formulation. Rather than beginning with a 7.5 cSt viscosity fluid and allowing a viscosity drop to 5.5 cSt, the Dexron VI fluid requires a starting viscosity of less than 6.4 cSt and a final drop to no less than 5.5 cSt.

Red Line D6 will begin at 6.4 cSt, and will drop to no less than 6.1 cSt over its usable life, according to Red Line literature. I've no idea how long is the "useful life" (for Red Line fluid). But the Dex-VI GM license specification is 42K cycles, using the GM cyclic shifting-test. This compares to the Dex-III H requirement of 32K cycles, and the Dex-III G requirement of 20K cycles. Note that Red Line D6 is not officially licensed by GM.

NOTE 4: Dexron III is no longer manufactured or licensed by GM. Well, sort of. While Dex-III is no longer officially licensed by GM to any aftermarket company, GM actually still has Dex-III manufactured, for sale through its car dealer network. Only it is not called Dex-III, nor is it sold under the previous Dex-III GM part numbers. "H" was the last version of Dex-III specified and licensed by GM.

The exact same original Dex-III H formulation is still manufactured by Petro-Canada, and is sold under a new GM part number. It is labeled as Manual Transmission and Transfer Case fluid. GM does not recommend the use of Dex-VI as a Dex-III replacement for manual transmissions and transfer case use. GM recommends Dex-VI only as a replacement/ upgrade for Dex-III (and Dex-II), only for use in automatic transmissions.

NOTE 5: All Red Line ATFs give a GL4 level of gear protection, according to Red Line literature. However, do not misunderstand this GL4 ATF protection-rating. This does not mean that Red Line ATF can be used where a GL4 gear oil is required. This is especially important to note when a GL4 hypoid-gear oil is required.

Gear oil and ATF contain different additive packages. But this does mean that Red Line ATF provides a higher level of gear protection than conventional ATF oils, when used in a transmission (manual or automatic), transaxle, or transfer case where an ATF is specified.

Transmission pressure switches are not directly related to ATF FM. But the pressure applied to the clutches during a shift, and the duration of the applied pressure, also affects how much slip, and therefore, the amount of clutch wear that occurs during a transmission shift.

If the transmission pressure switches are out-of-specification, undue trans-clutch wear can occur, especially during a shift.

Pressure switches (solenoids) can fail either due to the electronics, or due to sludge of the ATF and varnishing of the solenoid bores. Sludge and varnish can cause a pressure switch to overheat from malfunction, and fail electrically. You can control ATF sludge by using a synthetic ATF which is less susceptible to degradation from heat. And you can lower the FM in the ATF for faster shifts. Longer (slower) shifts with more clutch slipping, causes more heat transfer to the ATF.

Wear metals in the ATF can score the solenoid bores, causing lowered line pressure. Lower line pressure causes slower shifts, equals more clutch wear. You can control wear of pressure switches (solenoids) from metal particles, by installing a replaceable inline magnetic ATF filter. All older Honda models had replaceable ATF filters. Current models do not.

Here are some threads about the CL and TL transmissions, which are very similar (in operation) to the trans in the RDX.
A-110: DIY Guide to replacing 3rd & 4th gear pressure switch for 3G TL (2004-2006)

Here is some Info on the 2G CL/TL transmission .. ATF filter change .. Solenoids [my ed: pressure switches not solenoids]

My goal is a reliable 250K miles (400K km) for the transmission in a 2009 RDX, which is operated under moderately severe conditions. I do not believe that following the MID (multi-function indicator display/ Maintenance Minder), or the additional severe service requirements in the Owner’s Manual, will achieve this goal.

I have been using a low-FM type synthetic ATF for the past 10K miles, beginning at 15K miles on the RDX. I am currently running the 50% low-FM mix using Red Line ATF.

And I have added a replaceable inline magnetic filter to the transmission cooler line.
DIY – Add a Transmission Replaceable Inline Magnetic Filter
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Old 06-13-2016, 04:29 PM
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Really good info. Very well written, it's sad to see it's never been BUMPED......BUMP?
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