Transaxle Oil Analysis

[snijd]

Blackstone's analysis of factory-fill transaxle fluid at 20,000 miles:

Al: 47
Fe: 145
Si: 201
Insolubles % 0.2
Viscosity (cSt)@100C: 4.92

"The ATF from this transaxle is the original factory-fill and that is why there is so much silicon and insolubles present. The silicon is from sand-casted parts, lubricants and sealers that were used at the factory, while insolubles are an accumulation of oil oxidation due to heat & use, and metals from wear-in."

These results leave little doubt in my mind that an early fluid change is appropriate.

[dogfriend]

I received my second WS ATF analysis back from R&G labs (was PdMA) yesterday. Total mileage on the transaxle was 19,824, total mileage on the ATF was 10,262 miles (I changed the initial fill at 9562 miles). The new analysis is #311360, the previous one was #283540.

The most interesting part is that the Si went from 147ppm down to 46 ppm. This would seem to confirm that the Si is mostly the result of sealant and other manufacturing sources in the initial fill.

[Patrick Wong]

Given the used fluid tests taken at various mileages and posted above, it sounds like a good idea to do the first transaxle fluid change at 10K miles; followed by subsequent changes every 30K miles (i.e., at 40K miles, 70K miles, 100K miles etc.)

[dogfriend]

Originally Posted by Patrick Wong

Given the used fluid tests taken at various mileages and posted above, it sounds like a good idea to do the first transaxle fluid change at 10K miles; followed by subsequent changes every 30K miles (i.e., at 40K miles, 70K miles, 100K miles etc.)

I agree, although I will still probably sample at 25k and 30k just to see how the Fe and Al levels are. I plan to change again at 40k unless the analysis suggests otherwise.

[bwilson4web]

Everyone has their favorite data points and mine are viscosity:

24.6/5.5 - 40C/100C virgin
23.6/5.2 - 40C/100C first change
23.9/5.3 - 40C/100C second change (GREAT!)

The target is to change the oil just as the viscosity loses about 15%:

20.9/4.7 - 40C/100C 15% down viscosity, time to change

By a straight-line, it looks like you could go 6x between changes, 60k. However, 5x would be a good target for the next change with plenty of pad, ~50k miles of oil service life. But even 60k miles of service life is consistent with the other metrics we've seen for Type WS in the NHW20 transaxle.

Bob Wilson

[satwood]

Hi,

I'm right at 35K miles after 1 year on my 2007. I just ordered a case of Red Line synthetic ATF-WS and plan on making the change in a couple of weeks. Where should I send a sample to get analyzed (I'll pay) and should I just report the results here? Has there been any reported negative side effects from switching to synthetic ATF? I use mostly all synthetic oils in everything I own including the gears and transmissions.

Thanks
Steve

[EZW1]

Let's face it. Everything breaks down over time... it's called entropy. Now, just how fast if breaks down is predicated on many, many factors - some of which are how hard you drive, how hot the fluid gets, how hot the engine gets, local environmental conditions and temperatures, etc. To say the fluid will last 100k miles is a safe venture - after all, Toyota wouldn't say that if they knew the transmission was going to fail before then. But, common sense says to change the fluid at least once before then. Here in AZ, the summer temps get quite hot and everyone out here will change their motor oil every 3k miles instead of the manufacturers recommended 5k miles.

[drees]

Originally Posted by satwood

I'm right at 35K miles after 1 year on my 2007. I just ordered a case of Red Line synthetic ATF-WS and plan on making the change in a couple of weeks. Where should I send a sample to get analyzed (I'll pay) and should I just report the results here? Has there been any reported negative side effects from switching to synthetic ATF? I use mostly all synthetic oils in everything I own including the gears and transmissions.

Most people seem to use Blackstone Laboratories for their used oil analysis, I'd recommend them to keep the reports consistent.

I've used them for a while now for engine oil analysis and they seem to do a good job.

[bwilson4web]

Originally Posted by drees

Most people seem to use Blackstone Laboratories for their used oil analysis, I'd recommend them to keep the reports consistent.

I've used them for a while now for engine oil analysis and they seem to do a good job.

What do they charge for a 40C/100C oil viscosity test? The reason I ask is someone reported they were pretty high.

The reason for a 40C and 100C oil viscosity test is to see how it is holding up at low and high temperatures. A worn out oil will have a smaller ratio at the viscosity extenders fail. This is something a transaxle has to worry about because it spends more time in the low temperature ranges than does engine oil.

In contrast, engine oil tends to deal with high temperatures all the time. The time it is at a low temperature is very brief. IMHO Blackstone is quite adequate for engine oil but I understand rather expensive when trying to test both low, 40C, and high, 100C, viscosity.

Bob Wilson

[dogfriend]

Originally Posted by dogfriend

I agree, although I will still probably sample at 25k and 30k just to see how the Fe and Al levels are. I plan to change again at 40k unless the analysis suggests otherwise.

I'm going to skip the sample that I was going to pull out at 25k; I'm unemployed now and may need the money for something more urgent. Hopefully I will have found work again by the time I reach 30k.