ATF-WS lifespan?

Your on the right track. I dumped my 07's at 5K miles just to get all the manufacturing crap out of there. Although there's no torque converter so there's alot less wear and heat on the fluid so Toyota specify's a 100K refill but you still have a big mechanical chain and alot of gears so its all about gear wear. Its only 4 quarts no filter and pretty easy to change so its really cheap insurance. That PSD is expensive!!I will change mine at 30K intervals from here on out.

 

That was a waste and totally not needed.

 

Thanks Professor it wasn't. I changed to a different brand of GL-4 fluid.

 

I changed the initial fill at 10k miles. I think this is a really good idea, no matter what the official change interval is. My initial sample was high in Si , Al and Fe; the sample taken after the next 10k (20k total) was much lower for all 3.

I also plan on a 30k interval for subsequent changes based upon my and others UOA (used oil analysis). I'm getting close to taking the next sample.

 

Who would you suggest best to perform this maintenance. I am not a DIY type of guy. I hate bringing it to the dealer as their prices are insane. Can one of the lube joints be able to perform this maintenance. TIA!!

Dave

 

Could you give some more details on the type/brand. I am coming up to that point and I also always dump before 12K to get the crap out of the tranny. How dirty does the fluid in the PSD get?

 

The correct fluid as specified by Toyota is pretty cheap really. I think you will pay about $25US for 4 litres/quarts of WS fluid. I think myself that the best oil to use in the HSD is WS. I can't think of anyone who has done more analysis of the HSD fluid than Toyota and it's what they recommend. I change mine at 100,000km intervals as others who have had oil analysis of their used oils have recommended in PriusChat. More frequent changes in my humble opinion are a waste of oil and have an unnecessary impact on the environment. I expect to have my Prius until it has over 300,000km on it so I expect to do 3 HSD fluid changes at a cost of $75US total over the life of the car. Why wouldn't you do it with the right oil? What really have you got to gain maybe 5 or 10 dollars per change? What have you got to lose if the wrong oil causes harm to the transmission?

Yes I know I'll do 1 additional fluid change over and above what Toyota specify in that time but an additional $25 worth of fluid is cheap insurance going on other owner's experiences. I think changing the fluid more than that is over doing it as there are no clutches or bands to deposit friction material into the oil it will have a longer life than ATF in a conventional automatic.

 

And your point grasshopper? Changing any fluid before its time is always a waste of good fluids. Not to mention money. It is not being responsible nor smart in a world with limited resources.

 

How long do your parents plan to keep their Prius? If 100K miles or less, then don't worry.

If your parents plan to keep the car longer, or maybe will eventually sell (or give) it to you, then you might be motivated to keep the transaxle in the best possible condition since that is the most expensive hybrid-related component to replace.

I change the transaxle fluid at 30K mile intervals. You've seen other recommendations here to do an early change to get out the Si, Fe and Al that comes from the manufacturing process. It doesn't hurt to do that, and might help the ultimate longevity of that part.

I recommend using Toyota ATF WS which will cost ~$5 to $8 per US quart depending upon how rapacious your dealer's parts pricing is. You will need 4 quarts and tightening torque of the drain/fill plugs is 29 ft.-lb. You may also want to replace the two aluminum washers which will cost around $1 each.

There are many posts on PriusChat about how to change the fluid, including a few from me. Good luck.

 

djasonw,

I would NOT let one of the lube joints do it at all!! They may loosen the wrong drain plug & drain inverter coolant out (both drain plugs are near each other) & they likely would not tell you about it, so either you will be low on inverter coolant (or if they catch it & add it back in there could be air bubbles trapped in the coolant system & either way you could fry your $4,000 inverter.

Take it to the dealer & just ask for a drain & refill of the transmission/PSD (Power Split Device), for about $80-$85 but NOT a flush (usually around $130 or more) because there isn't a torque converter or any passageways to flush out like in a regular automatic transmission. The transmission oil in a Prius is simply used to lubricate the gears & chain.

Ken (in Bolton,Ct)

 

I did the cvt fluid drain initially at around 16,000 km, and was glad I did too. It drained very dark, and there was already stuff on the drain plug. I didn't have any sample bottles handy, so couldn't send a sample off

It's really, REALLY important to take off the correct plugs, or you will by mistake drain inverter coolant. Hobbit took this photo a long time ago, and I added arrows to show the correct drain and fill plugs



Always, always take the fill plug off FIRST. If for any reason the fill plug is buggered up, you sure don't want to find out the hard way after the fluid has drained. I learned that lesson the hard way, around 25 years ago

After the initial fluid change, I did it every fall. As I had a car ramp made of old railway ties at the hobby farm, it was a very easy job. Subsequent fluid changes the fluid drained very clean, and the drain plug was also clean

I think the biggest benefit to changing the Prius cvt fluid is an early initial change, then you can stretch it. Here in Canada, Toyota now recommends a cvt fluid change every 72 months or 96,000 km

 

It really is no different than draining and refilling a standard differential.

 

Our best data indicates:

• silicon leaching from sealant - based upon an external test, we found the sealant gives up Si and other elements pretty readily. Our belief is an early flush, 5-10k miles, will reduce this load.
• NHW20 - it looks like 60k miles corresponds to a 15% viscosity loss, a good time to change.
• NHW11 - it appears to be good for about 30k before a 15% loss of viscosity.

Bob Wilson