should I have fluids replaced at 60k miles?

Downsides would be wasting limited resources and contributing to recycling or pollution.. Also, $80. That's the big one for me.

The only upside is peace of mind and thinking you know more about cars than the engineers that made it. I follow the manual.

 

Following the manual is always a good 'thing'. On the $80.. the fluid cost is about $10/qt.. that's $40, and $40 for the labor.. not so bad.. I figure about 1/2 hour, and helping a local shop - a good thing too.. but we'll each make our own decision..

 

Right! so the evidence provided in lab test of used ATF tells us nothing. Since Toyota says 150k miles is "End of Life" for their cars (I keep my cars about twice that long on average), They don't suggest maintenance that prevents failures that would occur after 150k miles. Besides, your Tranny is only covered by the 5 year/ 60k mile warranty unless you pop for an extended warranty.

It is in Toyota's (and all other manufacturers') interest to market "low maintenance required" in their vehicles.

I still say refresh your ATF first at 30k miles and then every 60k miles thereafter.

JeffD

 

No, that's why lab tests should be done. But that's not what's being asked here. OP asked if they should be changed. According to the manual, that's a no. If a lab tests shows, otherwise, then we need to act on it. There's another thread on here about changing out the oil early and doing UOA's on it.
PIP transmission oil change @ 10K miles | PriusChat
Then we can dispute Toyota's recommendations with the facts.

This makes sense logically. But last I heard, companies including Toyota are struggling with reliability. Toyota actually shortened their OCI to 5000 miles in the early 2000's after all the problems with Camry's and oil sludge. I had a 1998 Corolla with a recommended 7500 mile OCI. I thought it was very strange to find my 2006 Corolla with a 5000 mile recommended OCI. Seems like the only reason we moved up to 10k OCI on our Prius is due to synthetic being used. Dino oil can still be used for 5000 miles according to the manual.

 

Thanks for the comments. All are valid points. I have the 150K mile warranty on my batteries - car purchased in CA. I'll plan on changing the ATF soon as I have 65K miles on the car. I'm not sure its necessary if the manual indicates 120K miles, but I drive up and down long grades in CO and I'm sure this puts stress on the components vs driving around on flat ground most of the time.

 

Getting the level right is extremely easy, as long as you don't overthink it start measuring what's come out, etc:

Just get the car level, drain, then refill until it starts coming out of the fill hole. Wait till it's just a drip or two (splish splash with a pinky to speed up the process), then bolt up.

For DIY, the fluid (4 qts or liters) will be about $40. I don't mind that at all, every second year.

 

But there's no evidence that there's any benefit to this early change, just a hunch from a very small group of owners. If these owners told you to get your knees replaced because they're bound to wear out, would you?

 

Good point. Preventive maintenance is common in cars but uncommon in humans.
I'm on the fence on this one. Is it wise to be more or less aggressive on the Toyota maintennace plan?

 

I will repeat the rational one more time.

A group of technically minded Prius owners have done a long term program of testing ATF in our Prii. There is a rapid build up of metallic load in the ATF in the first 30k miles that slows down as the gears in the tranny get "lapped in". An early drain and refill lessens this metallic load.

The Toyota type WS ATF in our Gen2 and Gen3 Prii loses viscosity (and some of its lubrication properties) within 60k miles of use. This is why we suggest following the early drain/refill with additional ones every 60k miles. Since I plan on keeping my 2004 Prius for a long time (now at 237k miles), I will continue to do this low cost ($100 at my dealer) preventative maintenance.

JeffD

 

I'm ready to jump in, bought the WS ATF today at the dealer, $10/qt. Not sure I'll do this soon, but at 65K miles, it's getting close. The ATF will be in the garage looking at me each time I go out there.. and I'm not one to spend $41.60 (inc tax) and let something sit around. Thanks for the discussion / advise.. I'll post every-step 'pictures' when this gets done.

Scott

 

Scott,

You need two washers, a funnel and a tube to do the job yourself. Make certain not to open the coolant drain by accident and it is a good idea to loosen the fill port before draining the ATF (just in case you have difficulty opening the fill port).

JeffD

 

Hey, what if you were to use a quality synthetic ATF, that says it is compliant with Toyota's ATF WS spec ?
Like Redline D6 or Amziol ATF FE, etc .
The viscosity is very similar.
Would that break down the way ATF WS does?

Just stirring it up ....

 

My personal opinion as a hybrid specialist is that I recommend replacement of the Prius transmission fluid every 30,000 miles. Cost of service is minimal compared to a shorted MG2 winding which usually causes the inverter to fail right behind it. We repair and maintain hybrid vehicles from all over our region. I can say without a doubt that the most common denominator on a failed inverter, battery or MG2 is burned transmission fluid. My personal hybrids get the trans fluid changed frequently. Individuals must decide themselves if there plan is to keep the car long term or do as little maintenance as possible and get rid of the car before the higher mileage causes an expensive failure. Hope this helps. "Mac"

 

Well said and agreed

 

Do you have an opinion on the type of fluid used?

 

Torque for both drain and fill bolts is 29 ft/lb. I'd suggest to take the underpanel completely off (mark the fasteners, there's at least a couple that are a bit different). You need a 10mm hex "socket" for both bolts. It's a good idea to remove the fill bolt first, just in case they're stuck or something.

 

This transmission is not a belt driven CVT like the Civic therefore the fluid should be a quality full synthetic but it does not have to be Toyota fluid. Hope this helps. "Mac"

 

^ Well, the grammar in the following excerpt from North American Owner's Manual is a little fractured, but the message is pretty clear. If you're adamant to use something else go for it (I'm sure some will), but:

 

Here's some food for thought.

On the third ATF change on my Wife's Durango I used full synthetic with the required additive. Around 5K-6K miles later the engine light came on. Diagnosis Code flagged the transmission so I immediately changed back to the Dodge recommended fluid and have had no problems since, with over 140K now on the vehicle. Edit: It is changed once a year since purchased.

Does this apply to the Prius, don't know, but probably not because it is not a traditional Automatic Transmission. Your vehicle, your experiment. Whether you use WS or an alternative, I do strongly advise you change all your fluids (and do other PM) much more frequently than any car manufacturer suggests. If does not make sense to wait until the properties required of them break down measurably. There is big money for Dealerships in repair from lack of PM, or from new car sales resulting from said money pit.

Preventative Maintenance is your cheapest insurance against failure. If you don't know how, learn, because it's a lot cheaper. You surely can't do any worst than the Jiffy Lube mechanics everyone is so fast to crack on. Be advised that the mechanics in Express Service at Toyota are "likely" not ASE either, let alone Master.