DRAFT Transaxle Oil Testing Results

[mcbrunnhilde]

<div class='quotetop'>QUOTE(tochatihu @ Nov 22 2007, 06:47 PM) [snapback]543064[/snapback]</div>

Blackstone has always seemed like a folksy homespun outfit to me and their FAQ follow in that vein.

Reading FAQ I also saw that their (engine-type based) universal averages are averages of *all* brands and grades of oil submitted. Thus they will not be meaningful at all in terms of calcium, etc., as components of additive packages.
[/b]

Yes, I noticed that as well. Do you think a test should be run on virgin transmission fluid (both types) to get a baseline?

Edited: Oops! I re-read Bob Wilson's post, and he did request analyses for both types of new fluid. I just joined the sat2 yahoo group so I can check them out. I'll post mine there as well when I get it in.

[bwilson4web]

Hi,

Pat and I have been sharing PMs and both of us thought it would be a good idea to share this:

<blockquote>Thanks for the great info, Bob! My sample is not at Blackstone yet, because I wanted to find out how important the 40C test was before sending it in (and, of course, find out if they could do it!). It will definitely be valuable to me, since I do seem to do a lot of short trips (6 miles or less). Looks like I'll send this to PdMA! I'm really interested in the results of the test, because I think I'm pretty easy on my engine, and I do balance my many short trips with long-distance driving now and then (I have 60,000 miles on my car in 3.5 years...). I hope other 2004+ owners do transmission oil samples to see if just certain people (or areas of the country) have a tendency to wear out the transmission oil faster--or if we should ALL change it at 60,000.

Pat

P.S. One thing I forgot to ask the dealership about was to make sure and get a mid-stream sample...I just hope someone with more than two brain cells took the sample and did it correctly anyway!

Hi Pat,
There are two questions: importance and price. Let's start with importance.

IMHO, low temperature viscosity is important because before the vehicle moves and for the first mile or so, this will be the viscosity found at the bearing surfaces. A very high viscosity under a lot of stress leads to 'shear down' when the mechanical stress can rip apart longer hydrocarbon chains as well as stress out the viscosity additives. The 40C and 100C tests also are used to calculate the viscosity index, a single number that as it declines indicates the oil is wearing out and the viscosity additives are disappearing (aka., shear stress.)

Of the two viscosity numbers, the 100C is most critical since that is closer to the operational temperatures. But the 40C number is useful to understanding what happens when the vehicle first starts out and during the 30 minutes it takes to warm-up. If you are doing mostly short trips, get the 40C value. If mostly longer trips, the 100C. So let's translate this into 'what does it do for my maintenance schedule?'

If there is a 15% decline in 40C viscosity and you do a lot of short trips, it is time to change the oil. If there is a 15% decline in 100C viscosity and you do mostly long trips, it is time to change the oil. If both show a 15% decline, you're late changing the oil. If both have less than a 15% decline, you've done an extra oil change and could have gone a little further. However, the Blackstone $20+ for the extra viscosity temperature test seems excessive.

My testing service, PdMA, does a basic oil test with 100C viscosity reading for $17.50 and with the 40C test, it comes in at $20 and includes the viscosity index. IMHO, this is about the right amount of money to pay for a complete viscosity reading, wear materials and additive levels. But each lab has their own equipment setup and configuration and it sounds like Blackstone only has one device for measuring viscosity at a given temperature. For them, the two temperature measurements would be a burden.

If the sample is already at Blackstone, go ahead and get what they'll give and chalk it up to 'lessons learned.'

Bob Wilson
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--------------------
Pat
2004 Salsa #7/AM "Gracie"</blockquote>

I wanted to add that the ICE and transaxle live somewhat different temperature profiles. I see the ICE coolant at 85C within 2-3 miles on any trip. However, the transaxle runs a lot cooler. On somedays, the transaxle barely reaches 40C. Yet if I get on the highway and travel at 65-70 mph, within 30 minutes the ICE will be in the 85-95C range.

Since the ICE is going to be at 85C, a single viscosity measurement at 100C is probably good enough. But my mix of commuting and high speed suggests I need to see both the 40C and 100C viscosity test results for the transaxle. BTW, this change in viscosity between 40C and 100C is what makes an oil a multi-grade like 5W-30.

Both labs appear to handle ICE oil testing with perfectly fine results. However, for transaxle oil, I prefer the 40C/100C viscosity testing because it gives a better indication of the lubricant performance under load.

Bob Wilson

[mcbrunnhilde]

Bob, thanks for posting our PMs where you outline the importance of the 40C test. I was originally going to go with Blackstone for my testing, and their basic test (for both transmission and engine oil) is $22.00. I found out that to add a 40C test would bring the total to $50.00!!!!!! I was told the reason for that is because they only have one viscosity machine, so they have to let it cool down overnight to do the 40C test. I'm sure they're a fine lab, and I know others have used them, but I'd MUCH rather pay $20 than $50. BTW I'm not getting a particle test from PdMA (the total price would rise to $34.50) since I don't expect my sample to be THAT bad....let's hope, anyway!

[bwilson4web]

<div class='quotetop'>QUOTE(mcbrunnhilde @ Nov 28 2007, 06:39 PM) [snapback]545476[/snapback]</div>

. . . . BTW I'm not getting a particle test from PdMA (the total price would rise to $34.50) since I don't expect my sample to be THAT bad....let's hope, anyway!
[/b]

Good point! The particle test really needs to be used to diagnose specific problems such as contamination or excessive wear and looking at the fine particle impact on oil lubricity, the ability of the oil film to reduce friction.

The literature indicates particles in the 3-8 micron range are the worst ones for adding drag because they can fit in the small spaces of bearings. These size particles are basicly 'smoke' dissolved in the oil. Even the better engine oil filters stop around 16 microns, which means they take out the chunks that can become future smoke but the the sticky smoke passes through.

A particle test is useful to quantify oil contamination and monitor excessive wear. So if your oil test comes back with high Si/Al amounts, the signature of dust/dirt contamination, the particle count can show the distribution of particle sizes. A second one say 1,000 miles later, lets you check on how much was carried forward and whether the source of the contamination was removed. As for excessive wear, chips are a bad thing, a very bad thing and means it is time to start saving up for an transaxle overhaul. In the meanwhile, think of using oil flushes to keep the particle load down.

Bob Wilson

[johnp]

I changed my transaxle fluid on my 2004 at 45,000 miles. I had a sample of the used fluid analyzed by Blackstone labs.

Al 112
Cr 3
Fe 206
Cu 19
Pb 2
Sn 3
Mo 1
Ni 5
Mn 5
K 1
B 46
Si 195
Na 5
Ca 114
Mg 7
Zn 12
Ba 26

SUS Viscosity @ 210 F = 41.9
cSt Viscosity @ 100 C = 4.76
insolubles 0.1%

Blackstone concludes based on insolubles and viscosity that the "oil was run too long"

I hope this is useful information. The moral of the story seems to be that it is a good idea to change the fluid.

John

[whodat]

I changed my transaxle fluid on my 2006 at 65,000 miles. I had a sample of the used fluid analyzed by Blackstone labs. Car is driven on California freeways near the coast. 100 mile round trip commute 5 days a week.

Al 101
Cr 3
Fe 219
Cu 18
Pb 2
Sn 2
Mo 0
Ni 8
Mn 5
Ag 0
Ti 0
K 2
B 47
Si 188
Na 4
Ca 106
Mg 5
P 253
Zn 10
Ba 39

SUS Viscosity @ 210 F = 43.6
cSt Viscosity @ 100 C = 5.28
insolubles 0.1%

[Delmartian]

Based on this advice, I will have the transaxle oil changed in my 2005 Prius with almost 60,000 miles. I have noticed a mileage drop and was wondering if this might fix it. The dealer did a series or tests and said everything was within spec so he could not explain mileage drop.

[Patrick Wong]

In general I would not expect a transaxle fluid change by itself to improve mpg.

However with my HiHy I noticed that the transaxle was overfilled about a quart when I drained the factory-fill ATF. After I refilled the transaxle with fresh ATF the mpg seemed to improve, not sure if that was a real change or my imagination.

[bwilson4web]

Originally Posted by Delmartian

Based on this advice, I will have the transaxle oil changed in my 2005 Prius with almost 60,000 miles. I have noticed a mileage drop and was wondering if this might fix it. The dealer did a series or tests and said everything was within spec so he could not explain mileage drop.

The temperatures have been getting cooler lately and this also impacts mileage. Do you have a record of mileage similar to the GreenHybrid.com mileage?

I found a reduction in cold temperature, rolling resistance with my first change. Since then, my transaxle oil's health has been excellent. I've also optimized my tires and wheel alignment. It has been difficult to replicate the hill rolling tests ... it rolls too easily.

Bob Wilson

[ETP]

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

Just to stir the pot a little. In the shop (8 years ago) we had close to 70% (actually it was 100% but I figured no one would believe me ) failure rate of changing fluid the first time at 90-140K ( within a couple of days the tranny failed sometimes 10 minutes). It was so bad we told people to not change their fluid if it had not been changed on a regular basis. Lot of factors to consider in those stats but we were convinced the stiring the sludge pot at very high mileage was costly.
And yes the pan was cleaned and a new filter but no flush because we did not have a flush unit.
We also noticed a thin layer of varnish on all those tranny parts and wondered if that was breaking loose and plugging the valve body and other passage ways. The bands, clutches and other internal parts seemed ok.