295,000 miles – should I change the transmission fluid?

It's not really a transmission, nor is it a 'transaxle' or a 'cvt.'
Feel free to disregard the thoughts of anyone who does not know what a 'power-split' device is or how they work.

Bottom line up front:
If YOU do it - then do it.

One of the YouTube giants in G3 DIY is "Nutz About Bolts"
Even if you do not DIY, you owe it to yourself to watch their videos so that you will be more familiar with what somebody else is doing to your car!
Nutz About Bolts Prius Maintenance Videos | PriusChat

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If you pay somebody else to replace your fluid, then you're rolling the dice - and your vehicle is already approaching the clubhouse on the back nine, but it probably will not hurt it.........'probably.'
if they use the right fluid and don't horribly over-fill or under-fill the [sic] "transmission" then they will not hurt it, much.
...probably.

SO.
If I were in your shoes - then I'd give you your shoes back.
Then I would either DIY this service or pay an independent mechanic about $150 to replace the gen-u-wine Toyota "ATF" fluid with the same fluid.
NORMALLY, I'm not a 'fluids' snob, but the power-split device in your car has stator windings in it and other things that might (probably will not) be damaged by bulk ATF fluid.

In your post you said....

This means you either DID it or HAD IT DONE.

This is an important distinction with a 10-year-old car because...remember....it's not a transmission.
It's a power-split device.

Good Luck.
I left my 'roastin pan' in the kitchen because curiosity is fairly important in learning,
AND the only stupid question is the one that you DO NOT ask!


- Good Luck!

 

The fluid wears out over time It just doesn't stay nice and red and clean. Power split device 3-speed transmission whatever so when you take a sample of this fluid if you were to do that it would look pretty gross and if you were to send that said fluid out to a laboratory and have it tested I bet it would come back as pretty gross with a bunch of big words like mayonnaise in the text for you to read because that looks impressive. Everyone the Prius I get looks like it's never been changed but that's about normal at 200,000 mi so I change it and I'm not using Toyota's fluid I have but I don't generally and I haven't had any problems and I have 400,000 miles on a few cars Prius just not the three those aren't worth my time here they're made for the masses other people need those I don't so I don't spend a lot of time watching videos about trying to preserve generation 3s or what have you A lot of other stuff is going to fall around the car besides the engine head gasket and what have you I would say change your fluid now with 300,000 on the car and you've already done a head gasket I imagine the next time the car breaks pretty much finished so that's not that far away I would imagine so maybe you'll be changing this car soon maybe it's values not worth discussing so maybe you won't change it I couldn't tell you.

 

It's not going to make anything better, why spend the time & money?

Some people do that sort of thing at 75k or 100k to feel better about making it to 300k+ miles. They already had a 99.99% of getting there without a lubrication issue, now they have a 99.999% chance of doing it.

You're already there. Why mess with success?

 

You should change it, or have someone change it. And ONLY use Toyota fluid.
The cost difference of any other brand is only about 2 or 3 dollars. NOT worth it.

If you are physically able to do it, you'll only need a 10mm allen wrench.
The hardest part is getting the car up high enough and level.
You can run a hose down from the engine bay to fill it, with a funnel.

"Lifetime" fluid mean until the warranty runs out....

 

I want my fluids after 100 or 150,000 mi in the transmission engine other things that have fluids to look like the new stuff when it went in at 150,000 mi when it's black I don't feel like it's doing such a good job maybe the manufacturer feels this way maybe not I don't know or care I'll just change it and be done with it in the grand scheme of things that's no money Will it fail because of the dirty black fluid I don't know but I know worn out fluids and oils generally are not doing well what they were doing before when the fluids were newer etc so what the heck We can't do this with engine oil and believe me I tried back in the old days I ran a car over 200,000 miles and never change the oil I added oil but I never changed it The car went on to do 400,000 miles It was an old TE series Corolla I think a 74 SR5 2TC engine built like a tank wonderful automobile.

 

Not sure why there’s even a question; yeah change the transaxle fluid, takes about an hour, and requires two washers, 4 qts of Toyota ATF WS, and a few tools. More info in my signature (on a phone turn it landscape to see signature).

 

I changed mine once, I assume for its first time, soon after I acquired the car with ~41k miles on it. I bought more Toyota WS fluid to do it again, but may not ever bother. Why? Because reports of oil-related transmission troubles on Priuschat are so rare, compared to threads involving several other well-known trouble spots.

 

Perhaps that's because "we" change the fluid????

 

They are very rare but I don't want that rare problem on my watch on my car on yours it's fine because I don't own it so if that can possibly be mitigated by $40 worth of changing the fluid every 5 to 7 years or some nonsense You got to be kidding me right But hey forge ahead. because more than likely you'll be not doing something else possibly that will cause the car to not be around. Most people don't keep cars any kind of time like I do most of y'all are out of a car by 200,000 or you're trying to be You have neighbors to keep up with you want something a lot newer just because you said so or you read about it in a magazine whatever that's just normal human stuff for most people I on the other hand. Have things that have been with me now 50 years some of that stuff you just can't have or get anymore. And I like my things on my terms my way. Not the way some manufacture says they've evolved to.

 

My vote: Yes

But only a drain and refill...not a flush.

 

Thanks for posting that you are at 295,000 miles and haven't changed it the transmission fluid. It is an example of the original fluid is lasting a very long time without transmission failures.

I am at 130,000 miles and haven't changed my tranny fluid either.

The point of changing your tranny fluid is to extend the life of the transmission. There's no point in changing it if your car will meet its end first elsewhere (e.g. headgasket failure). Maybe Toyota is right and it will last the lifetime of the car. Then again, maybe some drivers would repair the headgasket and eventually reach the tranny failure.

 

Why change the engine oil? Just wait until the engine fails.

 

Because if the engine oil isn't changed on a reasonable schedule, the engine will very likely fail early in life, whereas even if the transmission oil isn't, the transmission will probably never fail due to a lubrication issue. Such failure may be even less likely if the fluid is changed once early in life to get the initial wear-in metal out.

 

Those initial wear-in metal are stuck to the magnet inside the transmission which is what its job is for and draining the oil will not make those wear-in metal let go of that magnet. It's also not serviceable (the magnet).

 

There is no magnet on the 3rd-generation transmission drain plug. Are you telling us there's a magnet elsewhere inside the transmission? If that's true, it certainly hasn't been discussed much in Priuschat during the past 9+ years. I hear there was a magnet in the 2nd generation's plug. I replaced my drain plug with a magnetic one.

 

There's none on the drain plug of the Gen 4 transmission either but there's one on the bottom of the transmission case.

It's common practice so I would assume there is one there too on the Gen 3. He has a deep dive video of the Gen 3 transmission so may be he mentions it there. I didn't watch that one.

 

You guys are also forgetting about the two larger magnets in MEG1 & MEG2 and this only takes care of ferrous material, not non-ferrous material that just keeps floating around and gets stuck in fine passages. ie. cooling fin passages.

I'd go ahead and change it, it's cheap insurance against failure. I'm pretty sure it's black or very dark brown - varnished up and barely doing it's job of lubricating and keeping components cool. At least not doing it's job as efficiently as it could. Just my humble opinion. It's your car.
If you do change it, send some out for oil analysis and post. That way we can put this issue to bed, with actual data - not guess work.

 

All fluids wear out. Just because it's never been reported of a transmission failure
due to not changing the fluid, doesn't mean it does not happen.
The tranmission fluid is inexpensive, and changing it is fairly easy and quick.
It's electric, so there is not the same wear as a mechanical one. There are bearings in it though.
It would be the smart thing to do, changing it.