Changing the PSD fluid?

[hdrygas]

I just had the 30K service, mainly change oil rotate tires, change filters and check everything. I really needed to get in and out so I had my regular non dealer technician do it. He said the PSD (reads transmission fluid) looks really dark. He recommended changing it, but admitted that he has no reference as this car does not have a "transmission" in the ordinary sense. I figured it could not cause any harm but put it off. I am doing a lot of Pulse and Glide in the last 6 months. Is there a consensus on the subject. I am a sort of change any fluid that does not look right kind of person. What do you think? BTW he was amazed that my brake pads looked nearly unused at 30K. He suggested that I might try using my brakes!!!

[tochatihu]

Some Prius drivers including me have had this fluid changed, but I only know of examples with the classic Prius. In my case I did it at about 60k miles. I asked for a new pan gasket as well, so they could wipe out the metal pan and look for chunks. There were no chunks.

Bob Wilson had his fluid changed, got a sample analyzed, and found silica in it that caused him some concern. He has modified the air vent on his, thinking that there might mave been dirt entry.

As there have been something like 10 transmission failures reported on all the groups, it is a valid concern I guess. I am not prepared to recommend that everybody gets this done, but if you are willing to DIY your own engine and cabin air filters, the savings would cover an occasional PSD fluid change. Just a thought.

[hdrygas]

<div class='quotetop'>QUOTE(tochatihu @ Apr 28 2006, 08:29 PM) [snapback]247021[/snapback]</div>

Some Prius drivers including me have had this fluid changed, but I only know of examples with the classic Prius. In my case I did it at about 60k miles. I asked for a new pan gasket as well, so they could wipe out the metal pan and look for chunks. There were no chunks.

Bob Wilson had his fluid changed, got a sample analyzed, and found silica in it that caused him some concern. He has modified the air vent on his, thinking that there might mave been dirt entry.

As there have been something like 10 transmission failures reported on all the groups, it is a valid concern I guess. I am not prepared to recommend that everybody gets this done, but if you are willing to DIY your own engine and cabin air filters, the savings would cover an occasional PSD fluid change. Just a thought.
[/b]

The person I go to is honest and I think that following his direction can not do harm and might help. I am doing my own cabin air filters every 5K just because it makes my allergies so much better! Other allergy suffers may want to take note. You can build your own. I forgot to ask what the ICE air filter looked like. 30K seems long for that but technology does move on. It is not dusty around here for much of the year. We do get a huge amount of pollen here in the spring. It can turn you car yellow over night when the trees are at it! I might do it once a year instead of 30K. I am sure I could do the engine air filter looks easy.

[IFixEm]

<div class='quotetop'>QUOTE(hdrygas @ Apr 26 2006, 09:05 PM) [snapback]245941[/snapback]</div>

I just had the 30K service, mainly change oil rotate tires, change filters and check everything. I really needed to get in and out so I had my regular non dealer technician do it. He said the PSD (reads transmission fluid) looks really dark. He recommended changing it, but admitted that he has no reference as this car does not have a "transmission" in the ordinary sense. I figured it could not cause any harm but put it off. I am doing a lot of Pulse and Glide in the last 6 months. Is there a consensus on the subject. I am a sort of change any fluid that does not look right kind of person. What do you think? BTW he was amazed that my brake pads looked nearly unused at 30K. He suggested that I might try using my brakes!!!
[/b]

The oil starts out darker on the type t than dextron3, and the type ws is darker than the type t. WS is a dark blood red when new but I have started to notice on some of our customer cars it seems to actually be burning. 6 years of working on them and I did my first major repair 2 weeks ago....transaxle overheat code, mg 1 at 350*. Mileage was 120k I think, and an 02. Cust found an 02 inverter and transaxle assy for 3k at a boneyard.....low miles 15k crashjob. Customer did not want cores back. I now have a working core inverter and a not so well working core trans. I'm going to tear down the trans for my own curiosity and then donate it to a local tech school. The inverter is up for grabs. I had another 05 with 20k on it that got smacked real hard on the left front. The body shop wanted eng, trans, and HVbatt removed. The MG oil was nasty. Another customer in an 04 with 30 k on it came up 2 weeks ago from portland and he requested changing the MG oil. it was burnt. The stuff is supposed to be "lifetime" oil, but it apears to be measured in octopus years (they live 3 years). It's cheap and easy to drin and fill, I think the oil is expensive, but labor is cheap. From all I have seen in the last couple months I am starting to recomend a drain and fill every 30k as cheap preventative maint.
Regards, Mike

[tochatihu]

Thanks for that very informative post, Mike. I am going to recommend to Bob Wilson that he discuss Prius transmission fluid issues with you.

I may not mentioned it around here before, but I use the Graham Davies miniscanner in my 2001 Prius to monitor various parameters while driving. One that has caught my attention on a few ocassions is that the MG1 temperature will increase to values as high as 105 oC under extended heavy load at high ambient temperatures. MG2 does not get so high, and neither to any of the inverter or inverter coolant emperature measuring points. From these I conclude that the inverter coolant system is sized correctly for its job, but that under extreme conditions MG1 is not able to transfer its heat to the coolant effectively.

So far there is very little confirmation of elevated MG1 temperatures in other Prius of either model. Thus the possibility remains that mine in particular behaves in an atypical way. Will continue to monitor this issue, and start a discussion on it if more data appears.

[bwilson4web]

Hi Mike,

Doug suggested this thread and it looks like we're in the same pea patch:
<div class='quotetop'>QUOTE(IFixEm @ May 1 2006, 01:28 PM) [snapback]248058[/snapback]</div>

The oil starts out darker on the type t than dextron3, and the type ws is darker than the type t. WS is a dark blood red when new but I have started to notice on some of our customer cars it seems to actually be burning.[/b]

When I drained my NHW11 transaxle, I noticed it smelled of parafin . . . burnt. The test results were eye opening.

My car came from west Texas and I suspect heat stress cooked the oil but it also tested with a bunch of silicon. The only source I could see was the transaxle breather plug. When I disected the breather plug, I found it was a one-way valve and as I unscrewed it, I could hear the air hiss in. So I made a modification that keeps the transaxle at normal pressure behind the air cleaner.

I'll be sending another sample for testing but noticed that after 5,000 miles, even the Amsoil was darker than expected. At least it still smelled like transaxle oil and not parafin. I just regret I didn't drop the pan on the first change and wipe everything I could reach down. I found a fine layer of "black stuff" on every horizontal surface. I wasn't prepared to clean out the little gallery that still had a cup of oil but next time . . .

<div class='quotetop'>QUOTE(IFixEm @ May 1 2006, 01:28 PM) [snapback]248058[/snapback]</div>

6 years of working on them and I did my first major repair 2 weeks ago....transaxle overheat code, mg 1 at 350*. Mileage was 120k I think, and an 02. . . . I'm going to tear down the trans for my own curiosity and then donate it to a local tech school.[/b]

When you do, could you check out a couple of things for me?

1. Transaxle oil pump flows for after market cooler and filter? I noticed a couple of 'plugs' on the bottom of the outside case that suggests these may be blocking some ducting. I would really like to know if these plugs were removed, could pipes be connected to a filter and radiator?

2. Wet or dry area by transaxle breather plug? High on the transaxle, I am curious if this area really gets much transaxle oil. One of the ideas I had was to pour transaxle oil in via this port to help wash out anything that might have accumulated. But I don't know enough about the transaxle oil flow paths to know.

<div class='quotetop'>QUOTE(IFixEm @ May 1 2006, 01:28 PM) [snapback]248058[/snapback]</div>

The inverter is up for grabs. I had another 05 with 20k on it that got smacked real hard on the left front. The body shop wanted eng, trans, and HVbatt removed. The MG oil was nasty. Another customer in an 04 with 30 k on it came up 2 weeks ago from portland and he requested changing the MG oil. it was burnt. The stuff is supposed to be "lifetime" oil, but it apears to be measured in octopus years (they live 3 years). It's cheap and easy to drin and fill, I think the oil is expensive, but labor is cheap. From all I have seen in the last couple months I am starting to recomend a drain and fill every 30k as cheap preventative maint.
Regards, Mike
[/b]

I think the number is between 53,000 and 5,000 miles. I intend to get a year on this oil and change it again next spring. But this time, I'll have temperature data. One thing for sure, the oil get hotter after the car is parked.

I am concerned about the potential for latent heat cooking the oil . . . like in turbochargers. In some turbochargers, they have a small pump to continue circulating oil so the heat won't carbonize the oil and freeze the bearings. Speculation but I'm wondering if a pump like this might make sense. While you're in there, is there any way the oil pump cover could be replaced without removing the transaxle from the vehicle (or cutting a hole?)

When you get a chance, look for "ORNL/TM-2005/33" or "REPORT ON TOYOTA PRIUS MOTOR THERMAL MANAGEMENT". This report is looking at the heat management and concluded the bulk of it is via the transaxle oil. Worse, they indicated the existing cooling mechanisms may not be adequate. This is another reason why I'll be looking at the transaxle oil temperatures.

Well that is all for now. Hope it helps.

Bob Wilson

[hobbit]

Do any of the repair manual sections have *good* sectional views
of the HSD and transaxle case, such that one could really determine
the flow paths of the fluid? The pseudo-sections in the NCF are
rather unclear about what's open to what in there.
.
_H*

[bwilson4web]

<div class='quotetop'>QUOTE(hobbit @ May 1 2006, 11:48 PM) [snapback]248397[/snapback]</div>

Do any of the repair manual sections have *good* sectional views
of the HSD and transaxle case, such that one could really determine
the flow paths of the fluid? The pseudo-sections in the NCF are
rather unclear about what's open to what in there.
[/b]

I'm not terribly happy with the maintenance manual sketchs. Too often I'll take a part out and find all sorts of details not in the manual. I'm taking photos of everything (except when covered with oil.)

Bob Wilson

[hdrygas]

<div class='quotetop'>QUOTE(IFixEm @ May 1 2006, 11:28 AM) [snapback]248058[/snapback]</div>

The oil starts out darker on the type t than dextron3, and the type ws is darker than the type t. WS is a dark blood red when new but I have started to notice on some of our customer cars it seems to actually be burning. 6 years of working on them and I did my first major repair 2 weeks ago....transaxle overheat code, mg 1 at 350*. Mileage was 120k I think, and an 02. Cust found an 02 inverter and transaxle assy for 3k at a boneyard.....low miles 15k crashjob. Customer did not want cores back. I now have a working core inverter and a not so well working core trans. I'm going to tear down the trans for my own curiosity and then donate it to a local tech school. The inverter is up for grabs. I had another 05 with 20k on it that got smacked real hard on the left front. The body shop wanted eng, trans, and HVbatt removed. The MG oil was nasty. Another customer in an 04 with 30 k on it came up 2 weeks ago from portland and he requested changing the MG oil. it was burnt. The stuff is supposed to be "lifetime" oil, but it apears to be measured in octopus years (they live 3 years). It's cheap and easy to drin and fill, I think the oil is expensive, but labor is cheap. From all I have seen in the last couple months I am starting to recomend a drain and fill every 30k as cheap preventative maint.
Regards, Mike
[/b]

Mike that is way cool. I am sorry that I did not consult you but this was a really short term I need it quick, so I did not consider the dealer thing. I wanted it done before the Lacey fuel fair and Bryan's Automotive has been my go to person for, well more years that I would like to think. Bryan called the dealer and the "parts person" talked me out to changing it. I may bring it in. Fluids are cheep as far as I am concerned. I have learned a few things over the years but "click and clack the car guys" put it best "it is the cheep man who pays the most" That is totally been my experience. I have seen little down side over the years with over changing, fluid, belts or any other thing that suffers from wear. He did tell me that I needed to use the breaks from time to time! I guess I will see you soon? BTW why does everyone over fill my oil? I now have an exchange transfusion set up to pull a pint off after getting an oil change. BTW your shop is not exception! Is 4 qts the only thing the oil change people undersand?

[IFixEm]

Bill, the quick answer is yes, there is a way to add a cooler/more capacity. I tore the unit down yesterday and found several interesting things. MG windings were cooked on two of about 50 winding sets. Worlds biggest cow magnet....a drum about 7" diam, and about 10" tall. I thought I would need a cherry picker to get it out of the bore. It looks like clasics and next gen can utilize a cooler. I'll get some pics and try to post them. I'm going to be at the alt fuel fair with one of the company prius. I'll have the unit in the back for those that want to see the bowels of a PSD. Henry, I keep hammering on the kids, but good help is hard to find at $10./hour. I think I have finally broke their habbit of dropping tires down to 32! Baby steps. Got to go...more to follow. Bill I'm going to put together a "kit" of parts and try to find a local cust. to donate a car for a prototype.
Regards, Mike