to change or not to change trans fluid...

RUN... don't walk from this place - and please post which shop this was so others don't waste time or money.

Simple answer, just CHANGE the Toyota WS fluid.

 

Toyota says the Trans fluid is good for the life of the vehicle and doesn't need changing... I suspect person you talked to on the phone made up his own reason for why Toyota says that.

The truth is Toyota says that because they want you to only own your car long enough to love it so much you want to sooner than later buy a new on. As in their definition of a car's lifespan is a bit biased towards profit-motive compared to us folks that only buy used cars & want to do our own maintenance so as to get as much life out of them as possible.

The reason I changed my trans fluid was that in my experience back in the day a brand new engine usually has a break in period where you change the oil after the first 1000 miles because that's when it sheds more microscopic bits than any other time. So I figure changing the Transfluid once might limit that type of wear a tiny bit.

Bought an '07 Prius with 104K in 2012 and did trans fluid in 2013... I'm now at 230K with no issues other than usual Hyrbrid battery pack issues.

As for doing the work, the hardest part was finding a giant 24mm socket for the drain bolt. Was a bit larger than most stores kept in stock and I didn't want to buy a huge new socket set I didn't need just to get that one socket, nor did I want to use a more sloppy adjustable wrench on that bolt.

I used the long plastic tube technique to refill with Fluid I bought at Toyota dealer. The bozos who say you have to remove the power inverter to do this work are wrong. They're probably the same bozos that say you have to remove the front of the car just to access the headlamp bulbs to replace them, that's also wrong.

 

The previous owner popped my transmission (under warranty) around 100k, my guess was his long 'spirited' uphill driving (5k feet) combined with old WS fluid that hadn't been changed since the factory fill.

Pretty sure a 15/16 will fit. Always be sure to loosen/remove the fill bolt before draining out any fluid.

Fishing the plastic hose down is the best bet if you don't already have a fluid pump. Add until fluid comes out the fill hole (on a level surface), will be under four bottles of Toyota WS fluid.

 

Yea, 15/16 is 23.8mm so if you had a hammer...

But sometimes it's fun to do it the way the rest of the world does it?

I mean our country has alot of things wrong with it, but our failure to adopt metric when we "officially" transitioned to it in 1976 says alot about how often we create entirely unnecessary problems for ourselves.

 

Even though I'm a firm believer in the "force it if it doesn't fit" answer to life, you don't actually need a hammer for this job

Like many in the world I adapt to the prevailing norms, and occasionally go against the grain when looking for a little fun

 

I am also looking for information on this subject. I called an auto shop and they said if I change the transmission fluid, it may slip or cause issues.

My car runs fine but I would like to extend the life if possible. It’s a 2007 with 240,000 miles. I don’t know if the fluid has ever been changed as I bought the car at 200k.

Any insight as to if this job is worth it would be great. I’m just afraid that if I do it, it will cause problems with an otherwise working vehicle.

 

Avoid that shop, they know nothing about a Prius. A Prius does not have what you would call a transmission. It has 2 electric motors and some associated gears. And yes absolutely change it.

 

Toyota does not schedule a brake fluid exchange for the Prius either...and DOT 3 is also not lifetime fluid.

 

When they say the transmission fluid is good for the life of the vehicle, they say that it in hopes of selling you a new vehicle sooner than later. Having your vehicle just long enough to trust it and want to buy a new one is their ideal situation.

What it comes down to is some people like clean cars and some people like dirty cars. The people who like clean cars will argue that it's easier to get a car to last a long time if you keep it clean and repair even the slightest damage. And 200K miles on the same transmission fluid will create slightly more damage than changing it out once.

 

They said the same thing about that stupid transmission fluid for my 2005 Tacoma, except it’s way harder to check the level than the Prius. You have to start the truck with a cold transmission on level ground then take this level plug out right next to the drain plug. Then you have to wait until the fluid is like 170 degrees and if some fluid drips out it’s full. Completely stupid. Luckily Techstream tells you the transmission fluid temperature. And the dammed fill plug is right next to the exhaust pipe, so your actually better off overfilling it when you first start it so you don’t burn the crap out of your hands.

 

I can't offer any comment on the difficulty of trans fluid access or a change on your Prius.

I can offer that a power flush on an older mileage trans can (can) induce trans issues.
(A machine is hooked up to the transmission lines and the old oil is "sucked" out and the new oil "injected in")

A drain and refill, on the other hand, has been successful with many different vehicle brands offering no trans issues on higher mileage transmissions.
(Remove the trans pan, many replace a trans filter if applicable at this time, reinstall pan & gasket and refill through the trans oil fill hole.)

I'd say any oil refreshing would be a good thing...even if you only decided to "suck" a quart or two out the fill oil and then refill.

Reads like there is a procedure involving engine running and trans oil temp to attain proper level...you should get a service manual if you are DIYing.

Good luck in your decision.

 

Watch this video

Now, the Prius has no clutches, it has no torque converter, and it has no valve body.
Now watch it again ignoring the clutches, torque converter and valve body. There are now no downsides to changing the ATF.
A simple drain and fill is going to replace over 90% of the fluid, so no flush is needed. Just drain and fill. Toyota ATF WS



Picture of a gen 2 transaxle, showing the drain and fill bolts (always open the fill bolt first)

 

Exactly, and that’s why I said the guy should pass on that shop. They have no idea how a Prius works. They don’t have a transmission.

 

Toyota USA does not. However: Toyota Canada, as of 2013~2014, somewhere around then, started saying tri-yearly or 48K kms, whichever comes first.

FWIW, Honda Canada has said tri-yearly, regardless of mileage, as far back as I can remember.

Regarding the transmission issue: even if it was a conventional automatic, that no reason to not change the fluid periodically.

 

I went to a few shops and they said if it’s not giving problem don’t do it so I’m confused too cause I don’t want problems that’s why I wanted to change he didn’t say what just that it can mess it up

 

That CAN be true- sort of - on a conventional automatic transmission. On a poorly maintained and worn automatic trans, a bunch of fresh fluid can "trigger" a failure (that was going to happen anyway).

That's not the case on a Prius. The fluid in a Prius transmission is only there to cool and lubricate the parts inside. There are no clutches that can wear out and slip.

Changing the fluid on a Prius is simple maintenance that really should be done. Insist on it.

Posted via the PriusChat mobile app.

 

The prius, like the camry, are surviving long past their freshness date, all fluids break down under heat and undergo chemical changes with time heat etc. Some create metal destroying acids. Definitely replace the fluid at some point, what point, i have no idea, i did it to the 2005 at 250k miles.