ATF fluid changes ARE Required.

I always thought that clutches belong to the early steps of hybrids.
My bad, Volt has 3 to mock us.

 

No. I've replaced my transaxle fluid twice, with ATF-WS. I've got the sense to cherry pick Toyota's statements:

1. Never change the fluid? <There's drain and fill bolts, the procedure's outlined in the Repair Manual, I'm gonna dub this one pure showmanship, with callous disregard to the longterm health of the transaxle.

2. Use Toyota ATF-WS, other fluids may toast the transmission? <Hey, who am I to argue? The Toyota fluid is readily available, and a transaxle failure is something I don't want to tempt.

 

Next Gen PiP? The early test version was already good, limited acceleration and 62MPH were more than enough.
Prius is a proper Hybrid, not a gasguzzler like CS mode Volt.

You'll have to balance between the good thing and the bad things. Spare us to the 90' years technology giggle breath, like the Otto engine inside the Volt...

 

Cost per Mile? Did you consider calculating TOC?

 

That's an interesting statement: "box of gears and bearings"

With a high voltage electric motor that creates a lot of heat...

Dielectric properties of the oil? Is the aftermarket oil is more conductive? Can this cause arcing in the air gap, breakdown of the insulation on the windings, or current to be carried through the bearings, causing premature failure?

Guess why you have to use a special (different) oil and equipment for hybrid AC systems. As little as 1% contamination from charging the system with a machine used on normal AC systems can cause major problems.

The other thing the oil has to do in a Prius transaxle is cool the rotor/stator. What are the heat absorption properties of the aftermarket oil compared to OEM? Not just can it handle high heat...but can it move heat?

Know how everyone talks about WS turning dark pretty quick? Anyone know why it turns dark quicker than conventional ATF? It has to do with the detergents and dispersants in the additive package. You see, conventional detergents and dispersants that do a good job at keeping the oil clean are (drumroll)... more conductive.

Plenty of info on this in SAE paper 2013-01-0298 "Lubricants for (Hybrid) Electric Transmissions. There's also quite a bit of info concerning this and the above mentioned ability cool the electric/hybrid motor that's bathed in oil in patents:

• Sagawa, T., Ueno, T., Wada, H., and Aoki, T., 7,307,048 B2.
• Watts, R. F., and Noles, J. R., US patent 2008/0194442 A1.
• Smith, P. W. R., WO 2011/113851.
• Tingler, K. S., Sheth, K. K., O'Bryan, S. R., Yang, J., and Salma, T., 8,076,809 B2.
• Deskin, S. C., Shah, R., Rosenbaum, J. M., Bertrand, N. J., Lum, D. Y., D'Amico, T., and Schexnaydre, R. J., 2010/0279904 A1.
• Takei, M, Kanoh, T., Koide, H., and Fujii, K., EP patent 1,662,513 B1.
• Gong, Q., and Yang, J., WO 2011/147277 A1.
• Onumata, Y., WO 2012/132,055 A1.

The one thing that we can take from this is that electrical conductivity and the ability to cool play a part in the formulation of oil used in hybrid-electric transmissions. Oil for these transmissions is specifically formulated to work in the electric motor environment.

Another thing people bring up is the metal particles in the oil from transmission wear. Metal particles in suspension are far different than metal in solution. Particles in suspension do not create a conductive path, and therefore, do not necessarily make the oil more conductive. The metal additives used in the detergents, dispersants, and lubricants in the additive package are in solution (completely dissolved), and do add to the oil's conductivity.


People seriously need to get off of this "like" and "trust" rating for oils. The best oil for any given system is one that is certified. Note that "meets or exceeds" is not a certification. For instance GM Dexos, or BMW LL01. One grade of Mobile 1 carries the LL01 cert, another may not. Using oil that isn't certified has torn up lots or mechanical stuff in modern cars.

 

I've been using Maxlife and Supertech, WS oils in my 2008 Tundra 150K miles, for the past 50K miles. I routinely tow 8000 lbs over the Rockies never had a transmission related issue. If those fluids were subpar the way I use them would reveal any weaknesses. I just used a gal of Maxlife in the Prius and have complete confidence in its protecting the tranny assembly. All WS rated oils are synthetic, if they can protect my Tundra doing right by the Prius should be easy. Toyota didn't even think it needs a filter. If using Toyota oils makes for an easier nights sleep it's well worth the price of admission, I sleep fine using non Toyota WS fluids.

 

From the technical point of view, PiP and Volt share same EV technology, with different sizes. The greater the battery, more power output. But regarding ICE technology, PiP holds a very efficient engine Atkinson Cycle. Volt has a off-shelf Otto.

There is no chance in naming your car the highest tech car on the road, specially after your first sentence.

It is a proper 4 seated EV for some weeks at a time, carrying around a dorment ICE. Very high tech indeed...

See?

 

^^ You are too kind, Telmo
I group the Volt in the bin of not very good Prius imitations, despite taking 15 years to copy.

 

Modes? Clutches? Same tech involved, but more hardware, please go find a Voltec transaxle draft to check differences...Inverter/MG/Battery are similar.

1999? Prius was designed in 1996, released in 1997.

Also you paid for, you'd better be happy with it!

 

Your comment makes me think Toyota factory WS fill may be different than what you buy over the counter....with added additives.

 

Is this the interesting story or is there a link to the story somewhere? Assuming we're talking about a PIP and not a regular Prius (that would be an unfair comparison with the Volt indeed), why would it be anemic? Sure, the concept is different (and IMHO the next-gen Prius should have more emphasis on the E than on the ICE), but when you don't mind the revs, it's quite punchy (admittedly, never driven Pikes Peak).
And going down? I put mine (regular Prius) on ACC and it brakes electrically automatically. And when the the battery is full, it automatically uses the engine to brake.

Basically, a Volt and a Prius are two different vehicles. The Volt appears to be better if you can drive electric a lot, but when it has to use the ICE it's worse than a Prius.
Same difference as a Porsche 911 against a Toyota Landcruiser. Both have their strengths.

 

Even at a 3.0% lost in power every 1k' altitude, the nominal 99HP 1.8 Atkinson NA should give 55HP available if only ICE propels the Prius.
Anyway, since your personal experience is limited to the Volt in this track, I wouldn't declare this as a overhelming limitation of the superior design of the Prius
Regarding the brakes temp, Toyota has thought of that, and protecting the battery against a quick charge...

 

That's more like it. And technology marches "forward"...ops...sideways...carrying an unused seat and a dead weight under bonnet.

Unless instant response of nominal peak power at 14k feet is the new breakthrough test...