DRAFT Transaxle Oil Testing Results

[tochatihu]

etp, this may highlight the difference between Prius transaxle and conventional auto. trans. In the latter the fluid 'does work" while in the Prius it is only lube and heat transfer.

It is certainly possible that a Prius fluid change could mobilize varnish as passage-plugging goo, but it seems much more likely in the other systems.

[bwilson4web]

Originally Posted by ETP

Has anyone done a longevity/failure test of never changing the fluid versus every year? . . .

Not enough samples of transaxle failures. We've seen less than a dozen transaxle failures. But we were able to document an increasing load of contaminates in the oil and loss of viscosity.

Originally Posted by ETP

. . . plugging the valve body and other passage ways. . . .

As Doug pointed out, our transaxle are significantly different as there are no hydraulic operations in the Prius transaxles ... none. So when we change the transaxle oil, we restore the original viscosity and remove wear material.

Bob Wilson

[2009Prius]

Does PdMA still do oil analysis? Its website redirect to

R&G Laboratories, Inc or PdMA Corporation - Oil Analysis - Excellence in Lubricant Analysis

which does not seem to service individuals.

[bwilson4web]

Originally Posted by 2009Prius

Does PdMA still do oil analysis? Its website redirect to

R&G Laboratories, Inc or PdMA Corporation - Oil Analysis - Excellence in Lubricant Analysis

which does not seem to service individuals.

They still do. Give them a call but I haven't checked the prices recently.

My recommendation is:

• basic oil analysis - $17
• add oil index (same as 40C and 100C viscosity test) - total $20

The two temperature, viscosity test lets us know how well the oil has aged.

Bob Wilson

[ETP]

Originally Posted by tochatihu

etp, this may highlight the difference between Prius transaxle and conventional auto. trans. In the latter the fluid 'does work" while in the Prius it is only lube and heat transfer.

It is certainly possible that a Prius fluid change could mobilize varnish as passage-plugging goo, but it seems much more likely in the other systems.

Makes you wonder if another type fluid would be better than tranny fluid. But I suppose 0W20 may be a problem for some of the parts/maybe. CVT fluid should work.

[2009Prius]

How do you monitor the transaxle temperature? Can ScanGauge do it?

[satwood]

Good Morning Everyone,

As I reported earlier, I'm one of the owners testing the Redline D6 transaxle fluid instead of the factory WS. I made the change last year at 35K miles and had the factory oil tested as a baseline. Since then I have put 23K miles on the Redline oil and changed it for the first test sample. Total mileage at change was 57691. I had hoped to put more miles on but I've been out of town a lot. The car is used primarily for long highway trips, daily and weekly. The normal average mileage would be about 35K per year.

It looks like everything is in line or better than the first factory change except copper, phosphorus and Boron. The copper number went up to 19 but that looks similar to other people's data. The Boron value went way up to 268 - I don't know what that implies. Viscocity stayed up. I don't think I needed to change the oil again this early but I wanted the data. Anyone know what the Boron value would indicate? What does Phosphorus indicate?

My weekly mileage is right around 50MPG so the car is operating great and it drives excellent. I'll go for 35K miles on the next cycle and report again in a year or so.

Here is the quick data. Attached is a copy of the report with both sets of data.

Al 14
Cr 1
Fe 39
Cu 19
Pb 1
Sn 1
Mo 0
Ni 1
Mn 1
Ag 0
Ti 0
K 1
B 268
Si 42
Na 7
Ca 25
Mg 2
P 660
Zn 7
Ba 3
SUS Viscosity @ 210 F = 44.4
cSt Viscosity @ 100 C = 5.54
Flashpoint 425 deg F.
Water 0.0%
insolubles 0.0%

[2009Prius]

Thank you for the data!

I wonder what the error bars are on those numbers. Has anyone asked for them from the oil analysis companies?

[jayman]

Originally Posted by satwood

Anyone know what the Boron value would indicate? What does Phosphorus indicate?

Both are anti-wear additives. For engine oils, phosphorus is usually part of zinc dialkyldithiophosphate. ZDDP is commonly used to prevent cam lobe wear in flat tappet engine designs, which are not found in modern motors

Boron is usually boron amide and is usually used as an inhibitor to control acid buildup. It can also show up as a borax, which would imply a coolant leak

Since boron is multi-source, the testing of other additives and compounds will determine if the source is an additive, or a problem

[jayman]

Originally Posted by 2009Prius

I wonder what the error bars are on those numbers. Has anyone asked for them from the oil analysis companies?

Some are expected ranges, eg a xW-30 should test out at around 9.3-12.5 cSt @ 100 C. Others are "universal" averages, which are expected ranges

Most oil analysis will provide an expected range