10-23-2009, 10:21 PM
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#11 (permalink)
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Master EcoModder
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Another possibility I also remember is that left front axle, on the dailypic's 04 transaxle thread, was full of transmission fluid and mine had a left front axle replaced too but this may not be related to the trans failure. Could just be a seal problem that ruins the CV, not the other way around. Just interesting.
What kind of temperatures are you seeing? There could be much higher spot temperatures in the windings although you would think that the oil would carry away the heat better than air. Any other oil bath electric motors that you know of? There could be some solvent/corrosion effects from the oil if there are combustion by-products present. What happens to conductive/magnetic iron particles in that situation? Quite a soup, really.
Interesting problem and tough to diagnose. Would love to be a Japanese speaking fly on the wall at Toyota engineering meetings.
It could also be that this is just a normal failure rate for electric motors/transmissions. Are there any numbers on it? It can't be that bad due to the ravingly good customer satisfaction levels on these cars, just that when one does go it's sometimes $$$
I suppose, like anything else mechanical taking good care of it is the best insurance. Mine has no record of a fluid change in 100,000 miles. I guess the mechanic didn't bother reading the maint. intervals.
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10-23-2009, 11:41 PM
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#12 (permalink)
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Master EcoModder
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Picking up the car on Wednesday. Woo Hoo!
All arranged. Can hardly wait.
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10-24-2009, 06:05 AM
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#13 (permalink)
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Engineering first
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Quote:
Originally Posted by orange4boy
Another possibility I also remember is that left front axle, on the dailypic's 04 transaxle thread, was full of transmission fluid and mine had a left front axle replaced too but this may not be related to the trans failure. Could just be a seal problem that ruins the CV, not the other way around. Just interesting.
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That is an area I've had suspicions although the boot at the transmission is supposed to be packed with grease. If you happen to get into the shaft areas, I would be interested in seeing high magnification of the surfaces at the seals. It may also make sense to check the seal seat.
Quote:
Originally Posted by orange4boy
What kind of temperatures are you seeing? There could be much higher spot temperatures in the windings although you would think that the oil would carry away the heat better than air. Any other oil bath electric motors that you know of? There could be some solvent/corrosion effects from the oil if there are combustion by-products present. What happens to conductive/magnetic iron particles in that situation? Quite a soup, really.
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Welcome to my world! Here is my transaxle temperature study. I recommend seeking out the ORNL reports on the Prius. One of the reports on heat flow indicates 2/3d is via the aluminum case. So what we find is MG1 warms up and soon reaches parity with the ICE temperature. MG2 takes longer but its temperature seems to be fairly moderate until speeds begin to increase over 65 mph. Then we start to see MG1 and MG2 temperatures increase and the oil temperatures go up.
Quote:
Originally Posted by orange4boy
Interesting problem and tough to diagnose. Would love to be a Japanese speaking fly on the wall at Toyota engineering meetings.
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I'm so pissed at GM management for walking away from interesting problems like this 10 years ago.
Quote:
Originally Posted by orange4boy
It could also be that this is just a normal failure rate for electric motors/transmissions. Are there any numbers on it? It can't be that bad due to the ravingly good customer satisfaction levels on these cars, just that when one does go it's sometimes $$$
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So far, it looks as if the NHW20, more than 10 times the population of NHW11s, has had only one well known failure and the symptoms were consistent with a gear failure. I suspect a manufacturing change improved the NHW20 transmission resistance to the few failures we've seen with the NHW11.
Quote:
Originally Posted by orange4boy
I suppose, like anything else mechanical taking good care of it is the best insurance. Mine has no record of a fluid change in 100,000 miles. I guess the mechanic didn't bother reading the maint. intervals.
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When you look at the transaxle oil, be sure to have a clean, dry bottle to capture a sample. You don't have to send it for analysis but if you don't capture it that possibility is lost.
GOOD LUCK!
Bob Wilson
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10-25-2009, 12:28 PM
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#14 (permalink)
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Engineering first
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For good measure, there are Prius specific groups that tend to have participation by experienced Prius owners who have done a little more than ordinary things with their Prius: - PriusChat - Gen 1 group - web based, text and photos frequently monitored by Patrick Wong and Doug Schaefer.
- Yahoo Group "Prius Technical Stuff" - text messages with associated file folders with reports and photos. The searchable messages go back to 2000 so it has history. The folders got so full that two associated groups Sat1 and Sat2 were created to handle the overflow. My collected oil samples are saved in a folder under Sat2. First posts are moderated to limit SPAM and typically take 24 hours to turn around.
There is no reason why Ecomodder could not become a center of Prius excellence but these are established sites with history.
Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
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Last edited by bwilson4web; 10-25-2009 at 11:54 PM..
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10-25-2009, 04:36 PM
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#15 (permalink)
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Master EcoModder
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I'm just getting started on Priuschat and I signed up for Prius_technical_stuff but my first post there hasn't been put up yet. Waiting to be moderated?
I took a look at your studies. Great work. It's so good to have that kind of info. My Previa has been more difficult to work with but the info is there just not in that king of depth.
I hope Ecomodder's Prius community grows. It's a great forum.
I will take an oil sample for testing.
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10-25-2009, 11:50 PM
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#16 (permalink)
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Engineering first
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Correct about Prius Technical Stuff ... first posts are moderated. Michelle has been very good about such things. Still, the archives should be available. <GRINS>
Let's make sure to keep the folks here 'in the loop.' A hybrid isn't all that different, just more of stuff found on ordinary cars. The transaxle is amazing but that is only one part of the puzzle.
Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
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10-29-2009, 04:47 PM
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#17 (permalink)
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Master EcoModder
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Baby is home.
With lots of help from Dave and Julie.
The Prius was sitting in the parking lot of a repair shop. We didn't have a lot of time to get it loaded and catch the ferry. When we got there with the trailer, one of the guys said the mechanics would help push the car out of it's spot and get it lined up with the trailer since the transaxle was kaput the electric motor were cogging a lot and it was an uphill push. Dave and I waited for the mechanics to show up for a while but they were taking their sweet time so we decided to try pushing it ourselves.
We couldn't get it moving so Dave called Julie to help too. She came over and had just put her hands on the hood when we heard a commotion and six guys came running over, "Whoa! Whoa! We'll do that! We'll do that.", and within 10 seconds it was all ready to be winched up. Julie joked later that she was glad to have helped by being the passenger so Dave could take the HOV lane to get there on time as well as being the expediter of pushing.
No, Dave's not Amish. He's amiable though.
Rare chance to get a plan view.
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10-29-2009, 06:14 PM
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#18 (permalink)
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Very nice. I like the white cars.
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10-30-2009, 01:31 AM
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#19 (permalink)
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Quote:
Originally Posted by Daox
Very nice. I like the white cars.
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Yes, it makes the coroplast blend in! Very nice find, hopefully you can get her back up and running in no time with very little problems.
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10-30-2009, 02:00 AM
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#20 (permalink)
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Master EcoModder
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Quote:
Yes, it makes the coroplast blend in! Very nice find, hopefully you can get her back up and running in no time with very little problems.
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This is going to be honey's car so coroplast is strictly VERBOTEN! She tells me that Stainless steel is ok. She wants the salt flat disks and wheel skirts. My honey, she has a taste for the finer things...*sigh*
I will have to make the grill block a stealth unit because she like the Prius's "mouth". Working within these design constraints will be a challenge but I think I'm up to it.
Quote:
Very nice. I like the white cars
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I would never have chosen a white car before but I do love it now. Needs a good buffing and it will gleam!
__________________
Vortex generators are old tech. My new and improved vortex alternators are unstoppable.
"It’s easy to explain how rockets work but explaining the aerodynamics of a wing takes a rocket scientist.
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