OK to mix Transmission Fluid after Dealer didn't use WS

Option 1 insist on the pink OEM Toyota Fluid. Worth it.

 

An ATF flush doesn't do anything for these CVT transmissions. A simple drain & fill will get 99% of the old ATF out of these CVTs.

The only reason to flush a transmission is if it has a torque converter. A torque converter will hold half of a transmissions' ATF. The only way to get 95+% of the old ATF out, is to do a flush. No torque converters on your CVT.

Hope this helps..

PS. your transmission will take, just shy of 4 quarts of Toyota WS ATF.

 

Even then I wouldn't flush. When manufacturers spec a transmission fluid interval, they're fully aware of what percent will drain, and accordingly set the interval more frequently.

The one time I'd do a flush would be when something wrong had been put in. I once absented mindedly poured about a cup of motor oi into an automatic, before I woke up. That time I did a three-fold flush.

For OP, think now might be a good time to do a flush. Or maybe not, just do a single, thorough drain, refill with toyota ATF WS.

There's an even chance the dealership did use the correct fluid, just the service writer is out-to-lunch. It's a little amazing a dealership would use anything else, considering Owner's Manual has strong caution against using any alternate fluid.

 

I did a second ATF change on my old 2012 Prius C; just before an uninsured motorist totaled it out. It was around 60K miles of usage, and was very clean and bright pink; as expected. It was a lot cleaner than the 20K mile, initial drain and fill, very unexpected. That being said; there's plenty of Prius owners with more than 200K miles and have never touch their ATF. So very stout, reliable transmissions on these cars, even when abused. I consider not changing all fluids every 100K miles (required or not), abuse - everything eventually wears out. Getting contaminants out and refreshing the anti-corrosion chemical packets within those fluids is cheap insurance from costly repairs.

If you get a chance; take a picture of the mystery ATF the dealer put into your car and post it. That should give you an idea of how well that mystery ATF was holding up or not. $2.79 a quart seems a bit low for ATF, even in 2018 prices, unless it was cheap crappy Dextron III - which your dealership should've known better...

Gen 4 Prime ATF drain plug | PriusChat

 

Just curious: why do a flush on a Prius transmission?

 

Because he thinks the wrong fluid is in there?

 

Pretty disappointing a TOYOTA dealership did this. Also amazing the invoice is for 10 quarts of ATF. I wonder how they fit that into the case. Hopefully the tech did it right and it's just the 'advisor' who is the idiot.

 

The description on the invoice looks like “boiler plate” text, its word-perfect (which is rare) and uses expressions like “where applicable”.

there’s a possibility they did it by the book; the only issue is the invoice language?

Repair Manual info on transaxle fluid change is in one of my signature links IIRC (on a phone that turn it landscape to see signature).

 

Unfortunately; that would mean that the dealership committed fraud - sold 10 quarts and only used 4. If they place the 6 unused quarts in the trunk of the car; that should even out the scales...

This wouldn't be the first time I've caught a dealership, with their "hands in the cookie jar". About a decade back, a dealership body shop repaired a fender bender incident. A city truck backed into the front end of my car. The shop billed their insurance company for new hood hinges and didn't replace them. I noticed the hood vibrating at highway speeds. Pulled over to make sure it was secured and found loose hinges at the pivot points; not at the mounting points. The staff at the body shop acted like they were doing me a favor, by painting and replacing those hinges. Told me it would be at least a month before they could get to it. Their attitude did a 180, when I pointed out that they billed the insurance company for new hinges. The work was done in about an hour, on appointment the next day.

 

FWIW, liters of Toyota ATF WS are around $11~12 CDN apiece up here.

 

Sorry, massive brain fart!

 

Transmission should take around 3.5 quarts. As long as they don't use the wrong ATF and don't under fill it, it should be fine - very simple reliable transmission. Best of all, very difficult to screw-up the job. If they're not sure what to do, just watch one of the online videos.
IMHO, yes if they screwed something up, it should show up within 4000 miles.

 

Did you ever ask them about your suspicion? I doubt they'd use anything but Toyota ATF WS. For starters the Owner's Manuals warn that anything else could damage the transmission, and they're Toyota's front line.

 

Yes, for brake fluid owner's manual says any DOT3 is ok. But for transaxle fluid the owner's manual says emphatically, to use Toyota ATF WS only, and that anything else may damage the transaxle. I'm sceptical of a dealership in particular going against that.

FWIW, there's also a bulletin by Toyota, saying to only use ATF WS from freshly opened bottles. Guess it's hydroscopic or something, similar to brake fluid; if you DIY you want to open the bottle and use it right away, just recycle any left over at an oil recycle place.

There's some transaxle fluid replacement tips in my signature btw. On a phone turn it landscape to see signature.

 

You mean eCVT, Priuses do not use CVT, they have a planetary gear set.