Transaxle/Transmission Fluid Change - Dark Brown and Overfilled(?)

I did my first transaxle fluid change last night, and I'm not proud to admit that took me hours to accomplish. The car has 208,xxx miles on it, and I've only just started doing my own maintenance on 'er. I can honestly say... I don't know when it has the last transmission fluid change was, but judging by the color, it's been a some time.


After getting the car up and level, I opened the fill (top) plug and an absolute torrent of fluid came out. A comedy of errors ensued.

Since I wasn't ready for the fluid to shoot out nearly horizontally at my face, I dropped the plug into the basin. Once I fished it out of the miniature BP oil spill I was cultivating under the car with me, I quickly plugged the drain again. No easy feat when I have only inches between my mug and the rusty underbelly of the car.

Currently I only have access to low jacks/jack stands, so my personal protective equipment did some seriously heavy lifting last night.

After cleaning up, I decided it must be because the car wasn't actually level, despite all other factors arguing against it.

I opened the drain (bottom) plug, two catch basins ready, and let everything drain out. That's when my utter confusion has set in.

I let the car drain until the fluid slowed to a minute dribble. I measured what was in the basin, and not even taking into account the transmission fluid lakes forming around the garage, I took out over 4.5 quarts.

I closed the bottom plug and pumped in fluid through the top using the manual's recommended 3.6(ish) quarts.

I don't even know how it's possible to over fill it by that much. How could someone have filled it with so much extra fluid without it erupting back out of the filler plug?

 

Welp, that does make perfect sense, and I feel silly for not considering they may have filled it at an angle!

I realize cleaning up today that previously I was a bit conservative with the amount that came out, it was easily closer to five quarts, but likely more. In addition to the basin, it had filled nearly two 30oz Taco Bell cups (1.9qt). (Talk about a forbidden Cherry Pepsi).

Once I got the entire entire car drained including feeding a hose at the bottom to see if anything else could be siphoned out I poured in between 3.6 and 4 quarts. It didn't flow back out, but at least I know I got nearly everything out and put the correct amount in via measurements!

As for the mess, yeah, I usually keep a bin of dollar store cat litter on hand. Recently my parents have me a bag of Yesterday's News paper cat litter because their cats didn't like it. It works pretty well, although discontinued and similar products are far too expensive to normally be used practically.

 

I believe that may be part of how it ended up so overfilled. Like you said, if the place that did it originally had it cocked to the side, that meant they filled it until it came out (this overfilling it).

My Toyota manual specified 3.6 quarts specifically, and unfortunately I can't for sure say the car didn't settle and tilt. I'm personally confident having measured it before pouring it in that I should be good to go. There's no way I overfilled it, and little reason to believe I underfilled it either.

I bounced off ideas of how it happened with my roommate, and we remembered we had service done while stopping through Oregon. I recall the shop doing a bunch of extra work I didn't approve of, and then demanding I pay for it or they'd call the police and.keep my car. I ended up just paying it. It's not very charitable of me, but the impression we got was they knew we needed to get back on the road and thus didn't have time to make a big deal out of it. :/ (I planned to dig through my records now that this has reminded me and see if I can find the services they did, and whether this was part of it.)

As for the little vials, I've actually been collecting them as I go along working on my first cars. I kind of chalk it up to my specific brand of autism™, haha.

 

Oh yeah, make no mistake, I was only there for an oil change out of desperation. (I had an extremely important appointment to attend, and without a lengthy rambling story, we ended up at this shop.) I in no way signed off for the rest of that work, but calling the police and getting the law involved would have prevented me from getting to my destination on time, which weighing my options I forewent the $200.

In Oregon (at least at the time) they could put an auto mechanic's lien on my car and hold it as collateral until I paid. So if the cops did show up, I'd be SOL and it would have become a big legal fiasco involving small claims court. (This was years ago, so I the statute is up anyway.) It came down to choosing between being "right" and being efficient, and the latter was the smarter choice in this scenario.

I'll let y'all know what I find when I crack open the filing cabinet and spelunk for the invoice though!

 

I'm unsure, aside from what you mentioned, the car might have been at an angle? (More to follow regarding this.)

(Yeah I didn't do a super great job explaining it, got a little rambling!)

I looked through my files and found a receipt for tires I bought on the same trip, but not the one from that shop which is a bit odd.


I just spoke with my regular mechanics and it appears they're the ones that did the last change on it. I trust them, so I'm certain it was nothing intentional.

One of the guys up front likes to work on a hobby car, so he insisted I take it with a grain of salt, but he had a theory. Whomever worked on it a couple may not have been completely familiar with the Prius, and didn't recognize there being a difference between the CVT, and just use the regular procedure for it.

Is the "normal" procedure for a transmission fluid change different than for the Prius? He said some cars you'll pour fluid in and then run the car for a little bit turn the car off and then add more until it drips out. Once the drip steadily falls back that's when it's good. (I have no idea how accurate that is though, I'm merely the messenger.)

However I mentioned thinking there was something different about the Prius CVT, but at the time I couldn't really recall. Then I second guessed myself and couldn't figure out whether or not it was a just false memory. Found this thread and it seems to point towards yes? (Although still a bit out of my comprehension).

 

(The guy up front doesn't work on the cars at the shop, he schedules appointments. That's why he insisted it was just hobby car guy musings, not end-all be-all facts.)

Personally I don't believe the guy that did the change originally is at the shop anymore. They probably would have asked him about it. (They did add a note in their system though to be safe.)

I'm fairly certain they would have done those things had it actually caused any issues for me (during the recommended interval, of course. I waited far too long when I just did it myself. That's on me). They've easily done hundreds of dollars of work for me pro bono throughout the years, and that's another reason I really like them. ฅ^•ﻌ•^ฅ