This message is for everyone that has a sequential sports shift Honda / Acura automatic transmission. If you are unaware, Honda has had huge problems with them over the past 5 years. For those of you who are not aware of this: The Honda Prelude has the same 4 speed SS Auto that the earlier CLs and TLs have.

One manner to prolong the life of your tranny is to use synthetic ATFs. Unfortunately, only certain ones will work in the SS Auto's. One company that has a fluid that does work is listed below, and I'd like to get the word out to everyone about an issue that I've found with the fluid and how it's marketed:

B&M Racing “Synthetic Trick Shift ATF” (STS) update.

Well all, I told you “time would tell” on how B&M STS ATF is working in the Honda SS Auto.

The news I’ve got is mixed.

On the positive side B&M STS has some pretty nice qualities:

- Lower transmission temperatures (up to 20 degrees lower)
- Slightly improved shift characteristics

On the negative side B&M STS has some unexpected qualities:

- The flash point of the ATF is 345 degrees F (All other “synthetics” are over 400 degrees) (Honda ATF is 380 degrees F)
- The MSDS sheet for the ATF indicates it is made out of “hydrotreated heavy paraffinic distillate” @ <60%.

The positive aspects of the fluid are a nice change over stock Honda ATF. The transmission shifts smoother, even when cold under normal summer / fall temperatures above 50 degrees F.

Additionally, the operating temperature of the transmission is significantly lowered. This has a very positive effect on the life of the fluid.

On the down side, the B&M STS ATF is clearly not a true non-petroleum synthetic ATF as should e expected whenever the word “synthetic” is used. The fact that it has a flashpoint of 345 degrees in laboratory test indicates that the fluid is a conventional ATF. My initially suspicions were proven when I was able to obtain the Material Data Safety Sheet (MSDS) for the B&M STS ATF from B&M Racing.

I think it’s really important to take a second and drum this aforementioned point home:

B&M is marketing their “Synthetic Trick Shift ATF” as a synthetic product due to a legal loophole. The fluid is actually NOT a non-petroleum based synthetsized product. Until about the time Castrol Syntec came on the market, synthetic oils (lubricants) were called synthetics because they were completely created using chemical reactions to produce oils with the desired chemical properties. This is different than the process of refining petroleum in order to return a specific weight oil. The primary difference is that no matter how much you refine petroleum, you generally end up with a certain amount of the impurities found in the original substance. Generally, the process of removing paraffin (wax) from petroleum is known as “hydrotreating” or “hydrocracking.” The process of refining a petroleum product can technically be considered “synthesizing” a new product and allows marketing departments to call a petroleum based product a “synthetic” product.

The problem with petroleum based products is that they tend to be much more volatile than true synthetic products. What does that really mean? It means that non-synthetic products tend to evaporate into thicker lubricants which then cease to properly function in your transmission. Furthermore, as they evaporate they breakdown and coat your transmission with varnish, gum, or sludge.

Interestingly, the lab tests on an unused sample of Honda ATF indicated that its flashpoint is 380 degrees F, a full 35 degrees F higher than the B&M STS ATF. The viscosity index was also slightly better, but otherwise the fluids were very similar.

The real question is: What ATF should you use in your 5th Gen Honda Prelude?

Well, if you car is under warranty, you need to stick with an ATF that is RED in color. Honda will never know if you don’t have Honda ATF, but I’m sure some of you will want to be careful and use it.

So far, I’ve found that mixing B&M STS and Mobil 1 ATF works very well. The blend seems to provide a fluid that has both the shift characteristics that I’m looking for and the cold start characteristics that I require as well. I’m in the process of sending the mixed fluid out to the lab to find out if its combined chemical properties are what I’m looking for.

A follow on question is: Is B&M STS ATF worth paying the $8.00 a QT list price?

No. I’d have to say that installing an ATF cooler and using Honda ATF is probably a better choice. Over the life of your vehicle the $40.00 for a B&M tranny cooler is going to be cheaper and almost as effective as using B&M STS ATF.

It is possible that B&M’s STS ATF has a better additive package than the Honda ATF, but I’ve got no way to verify it. The chemical break downs listed in my lab tests only cover typical concerns such a TAN, trace minerals, and insolubles. Usually, ATF additive packages are compared against how well the additive prevents acid build created by worn out ATF. Both fluids seem to have comparable additive packages in the laboratory tests.

Personally, I’m much more likely to mix the Honda ATF with Mobil 1 or AMSOIL ATF's, as well as use a transmission cooler. I’ve found that using a 50-50 mixture of conventional ATF and synthetic ATF improves the shift quality dramatically, without adversely effecting the transmission while lowering the pour point of the ATF mixture. (The last part means that the fluid will shift better at colder temperatures.)

It is important to note that Honda requires fluids with low silicon to protect the seals. The B&M fluid meets this requirement at 12 ppm vs. Honda ATF being 4 ppm. The difference is somewhat insignificant and should really have no impact on the transmission’s seals.
B&M STS ATF does improve operating temperature (by lowering it) and shift quality over Honda ATF. However, if you are using Honda ATF or B&M STS you still should consider installing a transmission cooler.

I have contacted B&M Racing, I’ll post that message I send them as a reply to this one. I’ve not heard back from them, but will post that response when (if) I do.

-Gerhard

 

Original Letter to B&M Racing

B&M did call me back after I sent this letter to them. A guy named Frank got in touch with me and indicated that they were contacting the vendor (that makes the fluid for them) and would give me some of the information I requested. The problem is that he also indicated that to me that some of the information would not be made public. Of course I've got a problem with that as all other manufacturers (except Honda) will provide you with the ATF's chemical properties.

Here is the original message:

B&M Racing & Performance Products LLC
9142 Independence Ave
Chatsworth, CA 91311
Fax (818) 882-6694

ATTENTION: Technical Support

Re: B&M Synthetic Trick Shift ATF

Dear Sirs,

I’ve left a few messages on your technical support voicemail, and I’ve got a feeling they may be being disregarded. As a result, I’m sending you this fax message and will follow it up in postal mail.

I’ve got a 1998 Honda Prelude with a Sequential Sportshift automatic transmission. It was suggested to me that I try B&M Synthetic Trick Shift ATF as an alternative to Honda’s propiertiary Dexron III ATF.

There is not doubt that your fluid works well in the Prelude’s automatic transmission. It decreases operating temperature slightly, while improving shift quality slightly as well.

However, I do have a concern after sending the fluid to a laboratory and seeing the results.

The laboratory results indicate that your “synthetic” ATF may actually be a hydrocracked / hydrotreated petroleum base stock fluid. That is to say that your fluid may be a very clean standard ATF fluid and not a hydrocarbon engineered from “scratch” in a chemical process to create a completely different chemical.

There are two reasons I’m lead to believe this:

First, the lab results from the analysis of your “Synthetic Trick Shift” product indicate a flash point of 345 degrees F. This is very low for compared to any other synthetic ATF on the market. Mobil 1, AMSOIL, and Redline all have flash points that are 75 degrees F or higher than Synthetic Trick Shift.

Second, the pour point of your ATF appears to be much higher than any of the other fluids listed in the previous paragraph. This affects the primary reason that I purchased your product: cold shift ability. If the ATF thickens during exposure to cold climate, this will affect the shift quality of the transmission and will have an impact on proper lubrication of the units parts.

I would like further information on B&M’s “synthetic” ATF. I’m wondering if you would be kind enough to send me the standard chemical properties that are normally given for ATF’s by manufacturers: Specific Gravity, Pour Point ° C (°F), Flash Point, ASTM D 92 °C(°F), Viscosity Index, Viscosity cP @ -40C & cSt @ 100C.

It is possible that my lab results are off and I’d like to find out what the chemical properties of your synthetic ATF are in order to determine if it’s the best product for my car.

My concern is that your ATF is actually a marketed as a synthetic fluid due to a legal loop hole when it is not actually a true non-petroleum base synthetic product.


Gerhard

 

EricL, Scalbert want to comment?

 

Good Review.. I found this below data writeup most informative,, about synthetics and the use of this word.. http://www.synlube.com/synthetic.htm

I had contacted Both Mobil and Amsoil and they have both said not to use their Transoil products and to use only Honda Z1,, neither would give the chem breakdowns of what they are missing that Honda has.. It's been a year and I think I'll send out another inquiry to Amsoil, they seem to be the most responsive to my questions...(IMO)

 

I know for fact that RedLine D4 ATF will screw up an SS Auto. Witnessed that one directly...

Interestingly, the B&M fluid does work well. However, aside from shifting and thermal transfer characteristics, I'm really interested in cold shift ability.

Using 50-50 B&M and Mobil 1 has worked well for me. (Quite a difference.)

After the tests though, I'm thinking the Honda ATF / Mobil 1 or AMSOIL may be better...

-Gerhard

 

Interesting web site. Thanks.

 

Amsoil tech center reply about mixing and or Honda Z1 data.

"The Honda/Acura transmission fluid is proprietary to Honda. AMSOIL transmission fluids are not recommended for these vehicles at all – not even a blend."

Best just stick to Honda "Stuff"

 

AMSOIL's tech support line is covering their ass, not providing you a ture technical answer.

AMSOIL can be mixed with any other ATF. So can Mobil 1...

This is why I send my ATF to the lab and have it checked for compatibility.

-Gerhard

 

When I talked with Redline and Comptech, the D4 was NOT recommended.

The Redline High Temp ATF was recommended. I didn't do the tests, but Comptech has run the fluid for about a year now in a mix of Accords, CLs, Tls, and they seem to think that the stuff is working well.

As to the other combinations that you mention, who knows. I would be very concerned about any abrasive additives or any additives that impacted the ability of the clutch pack seals/o-rings to stay in great shape. If you loose one of them, the tranny is going to blow -- right now.

So, that's all I know for now...

BTW -- It is my opinion that the best bet for knowing about what's going on with the transmission temperatures is by getting at the thermo sensor located in the transmission (it runs straight to the PCM/PGM-FI) I’m making progress, but, there are a few issues that still need to be worked out. I'd like to see a set of data logs for pre-cooler, pre-ATF swap vs. post-cooler & post ATF swap. IMO, getting the temperatures INSIDE the transmission would be of great interest and would help protect owners who moved to the cooler (and I'm not saying that there is going to be a problem; it's just that there are some "dealers" that are a PROBLEM and the more ammo the better).

 

With the Prelude one of the intersting things that happened when I tried the B&M is that the engine temp went down 20 degrees. (Used the OBD II scan tool to get an accurate reading.)

I was fairly shocked.

In so far as abrassion, the Honda ATF is MORE abrasive than the others... That's why shift quality can be effected when using a normal Dexron III ATF.

The only thing that is a problem with the seals is if you have high amounts of silicon in the fluid. (That's from Honda.) AMSOIL, REDLINE, MOBIL 1 have 0% of the stuff.

It doesn't matter what fluid you use, heat is the big killer. I completely agree that knowing the actual temps would be nice. I suspect you could put a probe thermometer in the dipstick hole without any adverse effects.

 

Yes but Amsoil mission in life is to come up with compositions that can be used / mixed with other ATF.. Oil Analyzer Inc is the lab that works very closely with Amsoil,,, they are pretty good at knowing exactly what the chem breakdowns are in "ALL" ATFs... Not sure why Amsoil won't release a replacement product... But you have to remember Honda is not a oil company... they have ATF mixed and bottled by someone else... I think if we can figure out who Honda has as a source sub contractor we might know why other companies are kissing Honda's butt...

 

The reason is actually a legal one. After 1996 Honda stopped publishing any information (specs) about the products they use in their cars and their TSB's.

This is how Honda operates in Japan, and they decided to extend that to the US (and other countries) to prevent end user serving (e.g. forcing customers to go to the dealers).

I was able to get an MSDS for Honda ATF and I sent virgin samples out to Oil Analyzer and Black Stone Labs.

So I've got a pretty good idea of the differences between the fluids I've recommended.

There is no doubt that B&M works well. But you've got to change you fluid every 15,000 miles. Period. Otherwise the heat will destroy it.

Now, if you mix either Honda ATF or B&M STS with Mobil 1 or AMSOIL, you get much better cold shift characterisitics with a better ability for the ATF to survive heat related breakdown.

I've been doing this for about 25,000 miles without any problems.

Based on how the SS Autos fall apart I'm sure I would be on transmission 3 by now if the fluid was a problem.

-Gerhard

 

RE: heat – preaching to the choir…

Actually, I don't currently have a OBD II scan tool. And, when I asked Scalbert about getting temps from the OBD diag port, he said that the temperature for the slushbox was NOT available. If I misunderstood, then I presume that Scalbert will report back about this.

The 2001-2003 CLS/CLP has a sensor in the transmission that is in a good position to get the actual temperatures inside the transmission. However, I was actually considering getting at the signal going to the ECU/PCM (It's already there and well documented ... )

IMO, the 20-degree temp drop that you got via your internal temp sensor is the one that is of the greatest importance.

There are a number of different failure mechanisms in the tranny, but having a before and after heat log would be of the greatest benefit for "fighting" with Acura over the addition of a transmission cooler. (Our car’s fluid-to-ATF cooler is actually called a “warmer”/”cooler” and serves two purposes)

Do you have the temperature ranges (via the OBDII) for "factory/stock" vs. mods?

 

My main concern is two fold:

1. Not altering the friction characteristics so much that the clutches "slip" and wear too much (too slippery).

2. Abrasive or incompatible additives that would cause a seal failure.

There seems to be a "fine line" that can get crossed...

Thanks for the info...

 

Alas, I don't have the exact temp for my ride prior. I installed the B&M ATF and noticed that something was odd with the engine temp. During the summer it generally got hotter and the needle wasn't at the range it should be.

So I plugged in the tool and looked at the current temp.

I then went and found someone with the same model year and plugged in the scan tool on that ride... It was about 19 degree hot (I round up). Same exact environment varibles.

The B&M STS does work well. My only concerned with the stuff is that it's not a true synthetic fluid. So heat is going to kill it just like the Honda OEM ATF... That means that you should probably get a tranny cooler and install that.

Once you get the cooler, you just replace the fluid every 15,000 to 20,000 miles.

(I've spoken to quite a few Acura service guys and they've indicated that you really need to change the fluid regularly... don't use the service manual listed intervals.)

 

Well,

1) Friction: If the mixture I'm currently using shifts well in the transmission, then I'm going to have to say that probably not an overly serious concern. That is also one of the reason I suggest mixing Mobil 1 or AMSOIL ATF with the OEM fluid. This way you get the improved thermal transfer characteristics of the synthetics, while maintaining most of the friction characterisitics of the OEM fluid.

2) The additives are not incompatible. Accroding to Honda the only thing you want to make sure of that the ATF you have in the car does not have high levels of silicon in it. Silicon will destory the seals. B&M, AMSOIL, and MOBIL 1 have zero silicon.

Obviously, you should do whatever you feel safe with.