My Prime's first transmission fluid change :D

The Big Sleeze

Professor John Kelly from Weber State found a document that states the engineers thought it had a 100,000 mile Oil Change Interval.

Owners often find the first change to have the most wear. I advise drain and filling the ATF WS at 30,000, then 100,000 then every 100,000 miles. (This is just some guy on the internet's advice)

There are those here who experiment with other brands, but you know Toyota ATF WS works. (You will also need two aluminum gaskets at the dealer, if you are DIY)

If you have already exceeded 100,000 miles, no problem. The old wives tales about ruining your transmission by changing ATF too late, concern parts your transmission does not even have. (wet clutches and hydraulic logic bodies)

I would not compare your Prius transaxle (transmission and differential in one unit) to other transmissions, it is not a Torque Converter Automatic nor a Belt and Cone CVT. Since it does not have a Torque Converter, it does not need a flush, just drain and fill.

The simplest for me of Prosessor Kelly's many videos is

The most detailed for your 2020 is

 

Especially at such low mileage, I wonder if the factory fill has some special additives that make it appear dark. Has the darkness of the fluid been correlated with the condition of the fluid via UOAs?

 

Does it smell burnt?

Bob Wilson

 

I changed ours around the one year mark and 10K miles; it was definitely darker, significantly so. Later changes, at longer interval, were progressively cleaner. My take is that a brand-new transaxle is harder on the fluid, or at least builds up a lot more debris, due to gears meshing, manufacture residues or whatever.

I've no regrets about an "early" change, seems to avoid the transaxle "sitting in stale bath water" for countless years.

I'll take a possibly superfluous fluid change over a UOA any day.

 

Its dark because that's gear wear-differential wear. The majority of that gear wear happens at the first 5,000 miles maybe less.

The op will find all subsequent trans fluid changes to be drastically cleaner. In fact on my bought new 07 G2 I changed my trans fluid at 5K miles and it looked identical to his bottle color.
Then again at 35,000 miles and it was 100% cleaner. All the break in fluid was out of there.
At 75,000 miles it was a waste of time and fluid it looked perfect. I don't use WS I use an after market D6. I have trans UOA's in the G2 Trans stickies.

I would say the OP is good to go for the life of the car trans wise. Good job. Very little wear will happen from here on. if you really want to change it again go 50,000 miles first.

As far as contaminated fluid the same if not more goes for the Inverter coolant loop. The break in for that loop is much harder on that fluid then the trans fluid. It goes through raw aluminum channels and is easily contaminated by that aluminum. Again one change now will be good for the life of the car. I went through the same cycle with inverter fluid on my 07. Its all about that break in.

You will notice a jump in mileage with fresh inverter fluid. I did. Its the most important fluid in the car performance wise & mpg wise.

before you change it make note of the behavior of the fluid in the reservoir. Look at what it looks like with the car in ready. How aggressive is the circulation. If you change the fluid correctly you may see increased circulation. More flow in that reservoir. I did.

Toyota discovered that the G2 with its combined Inverter/Rad coolant chambers in the same rad box was not working well enough so the G3 and on has a separate coolant radiator away for the rad. No heat soak no cross heating. Made big difference plus there was the added heat load of the higher powered motors so much bigger Inverter coolant heat load than the G2 sees.



.

 

My brothers Volvo used an Aisin AW55-50 transmission that was notoriously prone to shitting the bed at around 250k km mark.. the reason? No tramsmission oil changes. Volvo, it appears, specs JWS3309 (Toyota T-IV) as a fill for life fluid. No Toyotas ever specs that fluid as a fill for life and no Toyotas ever had problems related to the fluid when it's changed at the specified interval of 96k km.. Volvos, it appears, are fine too when the fluid is changed in a timely manner..

 

Just a heads up. I changed my ATF at 10k km. Was sightly dark but bulk WS costs next to nothing for us anyway at work. Also changed engine oil and pourred a can of Liqui Moly Ceratec in there. Engine is smoother, hard to quantify how but it definitely is..

 

atf change at 10km? darn go green..you re wasting fuild that should be lasted for entire lifespan of the car...

 

Not really if keeping all that startup grit shortens the life of the car.

Many people here have done early changes like that and had a sample of the removed fluid analyzed revealing it was a good idea to change it.

 

Definitely go extra miles just to safe is fine, but my thinking is the same the below post on the 1st page of the topic.

"The owners manual doesn't mention changing the transmission fluid until it is at 60k miles under extreme driving conditions. If it is contaminated as soon as 2k miles, why don't they mention changing the fluid as early as 2k miles? I am thinking that following their recommended schedule would be good. Just trying to understand the extreme differences in maintenance schedules."

 

Because some are a lot more picky about the maintenance of their cars. I tend to keep my cars not that much for a long time but rather a ''far'' time.. My 2012 Civic Si, is tracked at every summer yet has 289k miles on the clock as we speak. Still rock solid! Maintenance was, as you may expect, meticulous.. As one of my teachers once said, ''I often saw broken cars because they were neglected but never happened the other way around..''

 

Instead of using a can of something why don't you just buy excellent oil. There's many choices out there. I use Redline 10-30 already has a ZDDP pack in it which these motors really like as they all have solid lifters and a great detergent too. It actually quiets the lifer noise down alot. The top end of my 07 was spotless after 165,000 miles..

 

I changed the primes tranny fluid at 30k and it looked similar (probably darker than the picture in post #1, if put in a clear bottle like @thatoneraccoon did ).
On another note as mentioned in post #165 above, today I got a snoot full of cold soak from the ICE's warm up cycle at 56 degrees F. It took about a mile and a half to complete, tooling around the neighborhood at 15 mph.
I also want to mark this thread to remind me to check the inverter coolant in the spring. I was going to do the coolant this fall, but didn't get to it in time.

 

Right!
Have an Oil Analysis done. It's not expensive. It's more scientific than saying "The color looks dark".

Here are some Prii transaxle Oil Analysis from before there was the Prime. Wordy, but real data is posted:
ATF fluid changes ARE Required. | PriusChat

So does the Prime actually call for transaxle fluid changes in the service schedule? !!

 

Only for vehicles for "Special Operating Conditions" with "Driving while towing, using a car-top carrier, or heavy vehicle loading", only then replacing automatic transmission fluid is scheduled item every 60K miles.

I did transaxle fluid change on my first Prius (2015 Gen3) at 30K miles even though the maintenance schedule was similar to PP and I never drove the car in "special operating conditions". I changed the transaxle fluid then probably because I read your original thread and the recommendation given there. But, I sold the car way before I could see the effect of the change. I also did the transaxle fluid drain-and-fill on my first PP (2017) at ~30K, but again I sold the car shortly after that, so I could not see the effect. I did not do anything on my second PP (2020) before selling it at less than 4Kmiles, and I probably will not do it on my current 2021 PP unless for some reason I decide to keep this car for a long time and start driving a long distance again. At my current rate of driving, the car will not hit the 60K miles mark for 10 years. I am sure I will be driving a different car before that.

 

@Salamander_King, The transmission/trans-axle is ON all the time; what's on the odometer is what's on the transmission. Most transmission breakdowns is due to neglect. While this transmission is a much simpler & a elegant engineering design, the chemistry will eventually break-down.There's no such thing as a lifetime ATF fill. Manufacturers that had tried this usually get a failure around 150K-200K miles, much sooner if you tow a heavy trailer up mountains. No harm, no foul - they're not on the hook for the rebuild.

IMHO: When a manufacturer states lifetime; it means to the end of the warranty period NOT what your expectations are, or your lifetime. I just consider an ATF change cheap insurance against a transmission failure. That's why the Toyota's routine maintenance states to check it at 30K. My experiences with my old 2012 Prius C indicates an early change, and then you can just drive it till it dies - or an uninsured motorist take it out - that's what happen to that car.

 

I totally agree with you on all accounts. What I am saying is that I am not going to keep my current PP for 150K-200K miles, nor do I attempt to use it with a heavy tow to go up mountains. It would be a relatively easy and cheap preventative maintenance for most owners thinking to keep the car for a long time. But for me, it is not necessary and will be a waste of my money and time. I will probably not drive this car out of the 60Kmile power train warranty period.

 

Just from fluid appearance, you're doing you're transaxle a favour, doing at least one drain-and-fill, anywhere from 10K miles onward, the sooner the better. It's about the same complexity and expense as an oil change.

 

I asked at the dealer about doing this, and they wanted $190 for the fluid plus labor.

Why?

 

Because they are greedy and they think they can ask whatever the price at personal whim, and most of the time get away with it. My first transaxle fluid change on my Gen3 was done at my local dealer, but I supplied them with ATFWS I purchased online. They charged me a labor cost of ~$80 for this service. I thought that's reasonable, I would rather use the dealer than DIY. Then, I had my 2017 PP also done at the same dealer. I was first thinking of DIY, but I just did not feel comfortable, so I took to the same dealer at the time of 30Kmiles service. They initially quoted me $380 total for the 30K miles service including oil and lube and tire rotation and transaxial drain-and-fill. But, in the end, after negotiating, the price came down to $175 total. Their pricing is so arbitrary, it is laughable.