I just changed the PSD fluid!

[Floyd]

I Jacked up the 05 Pr. thinking that it being level, I could drain and refill with the exact amount. When I started removing the fill plug, I could hear a sucking noise indicating that there was a vacuum. I expected the level to be even with plug. As soon as normal pressure was restored, fluid started gushing out and I had to jack the front end up more to keep from getting fluid all over me. I carefully measured the amount drained which was a little over 4qts., releveled the car and put 4qts back in. I didn't notice any unusual smell but the old fluid was somewhat darker than the new, and the magnetic plug had a small amount of black goo on it. To refill, I used a small funnel with a long piece of clear plastic hose which worked like a charm.
This fluid change was at 30k and I will probably do it again at 60k. I was wondering if the vent is designed to relieve pressure and operate under a slight vacuum (like a check valve) or is it possible that the vent is plugged?

[Beryl Octet]

<div class='quotetop'>QUOTE(Floyd @ Oct 3 2006, 09:35 PM) [snapback]327658[/snapback]</div>

I Jacked up the 05 Pr. thinking that it being level, I could drain and refill with the exact amount. When I started removing the fill plug, I could hear a sucking noise indicating that there was a vacuum. I expected the level to be even with plug. As soon as normal pressure was restored, fluid started gushing out and I had to jack the front end up more to keep from getting fluid all over me. I carefully measured the amount drained which was a little over 4qts., releveled the car and put 4qts back in. I didn't notice any unusual smell but the old fluid was somewhat darker than the new, and the magnetic plug had a small amount of black goo on it. To refill, I used a small funnel with a long piece of clear plastic hose which worked like a charm.
This fluid change was at 30k and I will probably do it again at 60k. I was wondering if the vent is designed to relieve pressure and operate under a slight vacuum (like a check valve) or is it possible that the vent is plugged?
[/b]

I'm not quite at 30K yet, but I will probably do this next spring. Is there a picture somewhere of where the drain & fill plugs are? Thanks!

[bwilson4web]

<div class='quotetop'>QUOTE(Beryl Octet @ Oct 4 2006, 10:38 AM) [snapback]327837[/snapback]</div>

I'm not quite at 30K yet, but I will probably do this next spring. Is there a picture somewhere of where the drain & fill plugs are? Thanks!
[/b]

Hopefully this will help:

http://hiwaay.net/~bzwilson/prius/pri_T_cold.html

Bob Wilson

[yakky]

What fluid did you use for replacement?

[bwilson4web]

<div class='quotetop'>QUOTE(yakky @ Oct 9 2006, 05:47 AM) [snapback]329979[/snapback]</div>

What fluid did you use for replacement?[/b]

For the 04-current Prius, Type WS.

For the 01-03 Prius, Type T is the OEM and there is an Amsoil ATF equivalent. However, some of us are moving to Type WS for improved fuel economy. NOTE: we don't have wear test results for Type WS so use it at your own risk and/or setup an oil testing schedule.

Bob Wilson

[hdrygas]

Was the smell of the old fluid some what like melted Paraffin or candle wax? Mine was quite discolored and had a smell that was different from the new. To me it was the smell of wax?

[bwilson4web]

<div class='quotetop'>QUOTE(hdrygas @ Oct 9 2006, 08:23 PM) [snapback]330365[/snapback]</div>

Was the smell of the old fluid some what like melted Paraffin or candle wax? Mine was quite discolored and had a smell that was different from the new. To me it was the smell of wax?
[/b]

My first transaxle oil smelled of paraffin and was pretty ugly. I had it tested:

http://hiwaay.net/~bzwilson/prius/pri_T_oil.html

Soon as I get 15k miles on this batch, I'm switching to Type WS with an aggressive testing schedule. This will help us determine the service life.

Bob Wilson

[Beryl Octet]

<div class='quotetop'>QUOTE(bwilson4web @ Oct 8 2006, 11:20 PM) [snapback]329914[/snapback]</div>

Hopefully this will help:

http://hiwaay.net/~bzwilson/prius/pri_T_cold.html

Bob Wilson
[/b]

Very helpful, thanks. I'd hate to have drained the inverter coolant by mistake.

[Ari]

For all you Prius veterans, can you please help define:

1) PSD
2) Transaxle
3) Differential

Are item 1) and 2) the same thing? And if 3) is actually a different item, where is it located and how would one go about changing the oil?

The 2005 Toyota maintenance schedule talks about changing the "Automatic transmission fluid" and "Differential oil" at 60000 miles on the page marked 11 in this PDF file:

http://smg.toyotapartsandservice.com/pdfs/..._service_05.pdf

Why are they separate items?

To make matters even more confusing, on priuschat people also refer to "CVT", "ECVT" and "Transmission" that the manuals don't talk about. I'm assuming that these are also synonymous with "PSD" and "Transaxle".

Based on the following thread, it seems like the Differential and PSD are part of the same unit in Priuses up to 2003:
http://priuschat.com/index.php?showtopic=1...tial&st=100

For a 2003, some recommend dropping the pan at the bottom of the engine. However, the 2004+ models don't have the pan - yet some readers still talk about having to drop the pan in order to change the fluid even with the newer engine!

BTW, I know what the transmission is like in a normal car and I've done ATF changes before, so that's not the hard part for me. There just seems to be more terminology for the Prius and inconsistencies between the maintenance manuals and confusion between the 2003- and 2004+ models.

[tochatihu]

For me, all the terms that appear to refer to the transmission are synonyms. There is just one lubricating fluid (supplied as T IV or WS, depending on model year) and there is just one coolant (LLC or SLLC), depending on model year).

Seems to me that the fluid changing guidance in the 'passport' cited above is copied from another vehicle/drivetrain technology (which would explain the separate differential and the reference to towing). It does not do much to inform us how long the Prius transmission fluid *really* lasts, under what driving circumstances, how we might know if it has lost effectiveness, and what damage it could possibly do after. Those matters are currently being worked out in this internet group (and others), before our very eyes.

Anybody with a Prius can contribute to this growing understanding. Once again, I wish that Toyota was doing a better job in advising us how to maintain Prius transmissions...hybrid synergy drives...spinning thingies.