Transaxle Oil Analysis

[ScottY]

I think it will be nice to collect analysis reports of the transaxle fluid as well.

Link to my report at 60,400 miles, link

High wear and insolubles plus low viscosity. Clearly it's not good till 100k miles like Toyota claims.

[efusco]

This is a great idea....if anyone knows where those other reports are please copy them to this thread. I actually sent Bruce Ertman a PM asking him to consider having Toyota look into this. I'd sure rather see Toyota just release a TSB/updated recs to have the transaxle fluid changed at 60k than have a bunch of reports of non-warranty blown PSDs when folks start hitting 120k miles.
Likewise, if anyone's done a transaxle change at 60k or sooner and got a GOOD report let's post those here too so we know how big of a problem this is.

[tochatihu]

The transaxle fluid analyses that Bob Wilson has been collecting are in the files section of the yahoo! toyota-prius-sat2 group.

I'd like to get his OK before copying them all over here, but I doubt that he would object.

Dr. Evan, I *strongly* agree that Toyota ought to publish something official about transaxle maintenance. Guidelines for acceptable levels of contaminants and viscosity would be ideal! But perhaps too much to hope for...

[Winston]

I really think Toyota as well as all of the other automobile manufactures know how quickly the fluid degrades. It is just a marketing/planned obsolescence issue. Even with the poor quality of the fluid from 40-50k on, the transaxle will still last well over 100k miles. As long as it fails after 100k miles, the dealers can just say that "parts start to wear out after 100k miles".

Toyota will never admit that there is a problem with the fluid, because they already know how it ages.

[bwilson4web]

Hi folks,

I kinda like collecting the reports in one, easily accessible area with good fetching characteristics. I'm not familar with PriusChat files organization but feel very comfortable with the Yahoogroup files. I won't stop anyone from making a snapshot copy but understand my future reports will still go to the Yahoogroup area.

As a way to move forward, I'd like to suggest the non-PdMA reports (Blackstone and others) get collected here and we have a reference to the PdMA files in the Yahoogroup. Eventually, in the Yahoogroup, I plan to make a master spreadsheet with all of the PdMA samples so folks can do their own analysis. But it gets harder when dealing with reports from different labs having different sets of data. It also raises the question of reproducibility between labs.

Regardless, I'll put in a reference to my DRAFT report to this area shortly.

Bob Wilson

[efusco]

<div class='quotetop'>QUOTE(Winston @ Oct 11 2007, 05:24 PM) [snapback]524256[/snapback]</div>

I really think Toyota as well as all of the other automobile manufactures know how quickly the fluid degrades. It is just a marketing/planned obsolescence issue. Even with the poor quality of the fluid from 40-50k on, the transaxle will still last well over 100k miles. As long as it fails after 100k miles, the dealers can just say that "parts start to wear out after 100k miles".

Toyota will never admit that there is a problem with the fluid, because they already know how it ages. [/b]

I don't know if that's accurate or not, but I suspect not. Toyota's reputation is heavily based upon the reliability and longevity of it's vehicles. If they start petering out at 120k or even 150k miles miles and requires a several thousand dollar repair that reputation will go down the crapper very very quickly.

I think it's more likely that their bench tests do, indeed, show the fluid to be fairly reliable at 100k. But now this real world testing and scattered reports of premature failures is calling their data into question.

[Winston]

<div class='quotetop'>QUOTE(efusco @ Oct 13 2007, 02:18 PM) [snapback]525220[/snapback]</div>

I don't know if that's accurate or not, but I suspect not. Toyota's reputation is heavily based upon the reliability and longevity of it's vehicles. If they start petering out at 120k or even 150k miles miles and requires a several thousand dollar repair that reputation will go down the crapper very very quickly.

I think it's more likely that their bench tests do, indeed, show the fluid to be fairly reliable at 100k. But now this real world testing and scattered reports of premature failures is calling their data into question.
[/b]

I'll believe that Toyota feels the fluid will last to 100k miles when I see ONE fluid analysis beyond 50k that shows the fluid is OK. I just don't think it is possible for a fluid to go that far and be OK. Especially with all of the break-in crud in there.

[efusco]

<div class='quotetop'>QUOTE(Winston @ Oct 16 2007, 03:12 PM) [snapback]526504[/snapback]</div>

I'll believe that Toyota feels the fluid will last to 100k miles when I see ONE fluid analysis beyond 50k that shows the fluid is OK. I just don't think it is possible for a fluid to go that far and be OK. Especially with all of the break-in crud in there. [/b]

The issue is what characteristics make the fluid "OK". While there's a quick drop in viscosity noted even after just a few thousand miles it also appears that it stabilizes at about 15% decrease in viscosity...it's not clear what the lower threashold of viscosity is that offers adequate protection.

I, personally, don't know the answer and suspect that Toyota is the only company who's done enough work with the transaxle to know the answer to that.

Likewise the other substances...what is the acceptible threashold for Si, Na, etc in the transaxle? Is it the same as for an ICE? Why, why not?



Look, I'm not defending Toyota any more than I'm attacking you. But it's important that we analyze this scientifically and objectively. And I'm not convinced that there is enough objective data to draw any absolute conclusions. There's enough annecdotal evidence out there that I changed my transaxle fluid at 60k and that I notified our Toyota rep (Bruce) and that I definately want it looked into. But let's not assume facts not in evidence either.

[Winston]

Don't worry efusco, I don't take anything personally. I am just stating my opinion. As far as the limits of wear metals, there is nothing special about the planetary gear system in the Prius. The acceptable limits that Blackstone uses are based on data from many, many analyses. It is not necessarily the drop in viscosity that matters, it is just that the fluid is so contaminated.

[jk450]

<div class='quotetop'>QUOTE(efusco @ Oct 10 2007, 06:29 PM) [snapback]523870[/snapback]</div>

I'd sure rather see Toyota just release a TSB/updated recs to have the transaxle fluid changed at 60k than have a bunch of reports of non-warranty blown PSDs when folks start hitting 120k miles
[/b]

Most knowledgeable independent technicians recommend regular fluid changes on "100K fill" or "lifetime fill" transmissions, hybrid or not. So for the most part, the problem takes care of itself. Some Toyota dealership techs recommend 60K changes, as well; if they don't like the factory recommendations, the are not shy to say so.

However, Toyota does help create a barrier to prudent service; some owners will pull out the maintenance schedule and pronounce the tech, who is recommending regular fluid changes, as "a rip-off."

I cannot emphasize enough the importance of finding a knowledgeable technician, and sticking with him or her throughout the life of the vehicle.