What services you need and what you don't

[apriusfan]

So, it sounds like we have a CVT in there somewhere. Maybe a CVT+, but still a CVT with friction elements that are in turn throwing off little bits of metal particles during a break-in process.

I am really not trying to be in anyone's face about this, and my apologies in advance if I am offending anyone, but it really seems as if there is a CVT in the HSD.

[FL_Prius_Driver]

The light bulb is about to go on. The CVT element is the motor to the left of the chain. By varying the speed of that motor/generator, the transmission ratio from the engine output to the wheels is set. There are NO mechanical CVT elements (pulleys, variable gears, etc.). VERY critical to understanding why this is so long lived is that there are no sliding elements (like pistons in cylinders) to grind metal, everything is a "rolling" type friction. Keep studying, this is fun stuff (at least for me).

[tochatihu]

FL_Prius, the only lab I know of so far for trans fluid is the one where Bob Wilson has sent samples. PdMA in Tampa FL. Just down the road?

The magnet is not on the draining bolt, but elsewhere in the pan. IIRC even the new model Prius still has the magnet, but there is no longer a removable pan.

For most complete trans fluid service of NHW11 Prius, buy also the sump gasket so that the pan can be completely removed and inspected and wiped clean.

As to whether Toyota suggests a fluid change, why just today in Prius Online, someone from Canada quoted some official servicing document saying trans fluid changes (NHW20) on 100 000 km intervals. It would not be unheard of for Canada to get 'out in front' on maintenance issues. Only there it seems is it officially recognized that extensive soot on the throttle butterfly can cause the 'slow start/no start' DTC.

[FL_Prius_Driver]

Thanks for the info. Probably a 1.2 gallon drive in my Prius. I thought it would be hard to retain the oil, yet check the magnet if it were on the plug. Retaining the oil while removing the pan is out of my league. The '01 is still about 40k away from the next change, so I have time to plan. Need to remember sump gasket.

[galaxee]

<div class='quotetop'>QUOTE(apriusfan @ Jul 1 2007, 06:36 PM) [snapback]471163[/snapback]</div>

So, it sounds like we have a CVT in there somewhere. Maybe a CVT+, but still a CVT with friction elements that are in turn throwing off little bits of metal particles during a break-in process.

I am really not trying to be in anyone's face about this, and my apologies in advance if I am offending anyone, but it really seems as if there is a CVT in the HSD.
[/b]

did you go to the site i pointed out? john has some extremely good educational stuff in there, seriously. there isn't a conventional cvt in the prius, and that's part of what makes it so long lived.

do your reading, grasshopper. you shall learn.

[IsrAmeriPrius]

<div class='quotetop'>QUOTE(apriusfan @ Jul 1 2007, 03:36 PM) [snapback]471163[/snapback]</div>

So, it sounds like we have a CVT in there somewhere. Maybe a CVT+, but still a CVT with friction elements that are in turn throwing off little bits of metal particles during a break-in process.

I am really not trying to be in anyone's face about this, and my apologies in advance if I am offending anyone, but it really seems as if there is a CVT in the HSD.[/b]

No need to apologize because most of us are not offended if you are determined to ascribe to wrong beliefs on this particular subject. I am only posting accurate factual information to assure that others are aware that you are spreading misinformation.

[apriusfan]

<div class='quotetop'>QUOTE(IsrAmeriPrius @ Jul 2 2007, 11:46 AM) [snapback]471636[/snapback]</div>

No need to apologize because most of us are not offended if you are determined to ascribe to wrong beliefs on this particular subject. I am only posting accurate factual information to assure that others are aware that you are spreading misinformation.
[/b]

Well, where are the wrong beliefs? There is some way of converting energy to forward or reverse movement. Whether you agree with my contention that a CVT-type of approach is what is actually occurring is a point of debate. While we are on the topic of a CVT, I would submit the following URL for your consideration:

http://www.toyota.com/prius/specs.html Go to the transmission section, and low and behold, direct from the manufacturer: "Electronically controlled continuously variable transmission (ECVT)"

Reaching a conclusion that I am spreading misinformation is not supported by the posts that I have made.

[IsrAmeriPrius]

<div class='quotetop'>QUOTE(apriusfan @ Jul 2 2007, 12:35 PM) [snapback]471685[/snapback]</div>

Reaching a conclusion that I am spreading misinformation is not supported by the posts that I have made.[/b]

You are the one who has disregarded all the technical information which was posted by others to explain how the Prius' "transmission" works.

It is a waste of everyone's time to continue this dialog with you. Good bye.

For everyone else, here is an explanation of the difference between the Prius power splitting device and a conventional CVT:

"True" Continuously Variable Transmission
The more gear ratios we have, the more choices we have in setting the engine spin rate for any given speed. This allows us to call for power when we need it by revving high but to cruise economically by lowering the engine spin rate and reducing losses associated with the fast-moving internal engine parts. A conventional CVT has an infinite (or a very large number) of gear ratios. It selects a ratio that can deliver to the wheels the power being demanded by the driver, but keeps the engine spin rate low within this constraint to improve economy and engine life. As the car picks up speed, the transmission continually shifts into a slightly higher gear. The result is that the pitch of the engine tone stays fairly constant and the acceleration falls off smoothly, instead of in steps, as the higher gear ratios have a smaller multiplying effect on the engine torque.

The advantages of a CVT (selection of the best gear ratio at all times to balance performance and economy) are considerably offset by efficiency and reliability problems. Efficient and durable toothed gears, the mainstay of step transmissions, cannot be used. Instead, an arrangement of belts and pulleys is necessary with a mechanism to vary the effective diameter at which the belt passes around the pulley.

The Prius Transmission
The Prius transmission produces one of the effects of a CVT but not the other. The spin rate of the engine can be selected to produce the required power but otherwise to spin no faster than is necessary to maintain fuel efficiency. The Prius engine tone therefore sounds as if the car has a CVT because it does not rise as the car picks up speed. Instead, it rises and falls with power demand, in other words, how hard you press on the accelerator pedal. The Prius transmission does not, however, multiply up engine torque at low vehicle speed. This is because it has only one gear ratio. Effectively, the engine is coupled to the wheels as if the car is always in top gear. This would be a crippling limitation, if not for the presence of a powerful electric motor in addition to the petrol engine. With this motor adding its considerable torque, people have said that the car feels as if it's always in 1st gear![/b]

[FL_Prius_Driver]

Apriusfan - I have not forgotten that your original post was a very welcome question about the idea of changing the transmission fluid at a short initial interval. Somehow this got sidetracked, so let's return to being helpful.

The overwhelming evidence presented by those that backup their experience is that Toyota (Japan) is over optimistic claiming no changes needed (60k, 600k?). The vast majority would agree that 60k miles seems to be the most sensible interval and I have yet to see a presentation of evidence to the contrary, but cyberspace is large and my time less so. I have had this changeout some time ago and think that it was money well spent. What I did not do is specify what fluid to use as replacement. This is what I know now to specify next time.

The Prius ECVT is an fasinating implementation of a motor driven, planetary gear transmission. Imagine being told by a repair shop that the clutch needs to be replaced You already know that's probably not quite right.

[apriusfan]

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Jul 2 2007, 08:16 PM) [snapback]472026[/snapback]</div>

Apriusfan - I have not forgotten that your original post was a very welcome question about the idea of changing the transmission fluid at a short initial interval. Somehow this got sidetracked, so let's return to being helpful.[/b]

Yes, I was starting to wonder if I had mis-posted to a thread that was debating whether the Prius CVT was or was not a true CVT....

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Jul 2 2007, 08:16 PM) [snapback]472026[/snapback]</div>

The overwhelming evidence presented by those that backup their experience is that Toyota (Japan) is over optimistic claiming no changes needed (60k, 600k?). The vast majority would agree that 60k miles seems to be the most sensible interval and I have yet to see a presentation of evidence to the contrary, but cyberspace is large and my time less so. I have had this changeout some time ago and think that it was money well spent. What I did not do is specify what fluid to use as replacement. This is what I know now to specify next time.[/b]

Out of curiosity, are you referring to a replacement fluid other than the Type WS fluid?

<div class='quotetop'>QUOTE(FL_Prius_Driver @ Jul 2 2007, 08:16 PM) [snapback]472026[/snapback]</div>

The Prius ECVT is an fasinating implementation of a motor driven, planetary gear transmission. Imagine being told by a repair shop that the clutch needs to be replaced You already know that's probably not quite right.[/b]

I think the ECVT is just one of a number of very innovative bits to be found on the Prius. In the interest of information sharing, I will try to remember to post a used oil analysis when I swap out the CVT fluid.