Dealership shenanigans?

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May 28, 2025
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My spouse has a midd'ish 2010's Prius C. I personally changed the transmission fluid in it at 100k. I remember that the fluid while fairly darkened, was still reddish.

The second time it was changed at 175k, I brought it to the Toyota dealer because it was wintertime and I don't have a heated shop/garage.

What's weird is that I recently changed it again at 221k, and it was black/super dark. It looked worse after 46k miles than it did after the initial 100k. It makes me wonder if the Toyota dealership even changed it? I've read/heard that because Toyota deems the ATF in these cars a lifetime fluid, that it is not uncommon for them to refuse to do this service, or to say they will and don't actually do it.

Anyone have any experience with this or have heard anything about it? I definitely won't be taking it back there ever if I can help it. Same place wanted 5k to change the hybrid battery pack, when I found a guy who used all brand new OEM batteries do it for less than half that. Sure, overhead and all that jazz, but even some other dealerships in the area were like a thousand cheaper.
 
I doubt there was any wrong doing. There's 221k miles on the transmission, you can't expect fluid to look like it did many miles ago. There could be an issue developing with the transmission after 221k miles.

When hybrids get old, it often itsn't worth putting batteries in it and they are scrapped out or traded in. Myself, I would have to do some hard thinking putting thousands into a 15 year old car with a lot of miles.
 
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I don’t think you have any reason to doubt that the work was done at 175k. By the time the transmission got to you at 221k, it was far more worn and degraded than it was at 100k. Love that you are keeping this car going, but maybe a little perspective: it’s the cheapest Prius, well into its second decade, with high miles and failing batteries. I assume that the transmission is working okay and don’t see why you are claiming dealer shenanigans that happened years ago (most likely did not happen imo) when the real questions are whether you invest more in this aging sled.
 
It's impossible to know if someone did the job they billed you for or not.

Are there not cheaper fluids with dyes which are known to blacken quickly once use begins?
They may have done the job and not used bottled OE ATF. Ha-a compromise on 'dealership suspicion'.
 
I would drop the pan (is it possible on this one?) for cleaning (clean / add magnets) and then do a drain & fill at every/other engine oil change until it stays clean & clear. Then remove the pan after ~ a year for another cleaning / inspection.
 
Prius C? This is likely using Toyota WS transmission fluid?

I'm wondering if you are being mislead by the WS fluid, which tends to look awful after a while, while starting out looking darker in the beginning. Reason being, as a hybrid, I'm not sure what is going to beat up the transmission fluid. No clutch material and no torque convertor to roast the fluid.
 
Prius C? This is likely using Toyota WS transmission fluid?

I'm wondering if you are being mislead by the WS fluid, which tends to look awful after a while, while starting out looking darker in the beginning. Reason being, as a hybrid, I'm not sure what is going to beat up the transmission fluid. No clutch material and no torque convertor to roast the fluid.
Dark transmission fluid is likely from metal wear and magnets that are already loaded with material, no longer cleaning.
 
I doubt there was any wrong doing. There's 221k miles on the transmission, you can't expect fluid to look like it did many miles ago. There could be an issue developing with the transmission after 221k miles.

When hybrids get old, it often itsn't worth putting batteries in it and they are scrapped out or traded in. Myself, I would have to do some hard thinking putting thousands into a 15 year old car with a lot of miles.
These cars from this time range are known to get to up to around 500k+ with good maintenance/care and with the barest maintenance/care often go to around 300 to 350k. I think there is plenty of life left in the car.

These transmissions are extremely well built and very easy on transmission fluid. There is not a lot to wear. If anything, doesn't a lot of the wear actually happen when the car is new and first starting to be driven? If I could do things over, I would have changed the trans fluid earlier than I had.

It just seems a little odd that it only went 46% of the miles (and probably time) and yet was even darker. If it was a more regular transmission, I'd accept the whole, it's old and wearing down premise.
 
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I don’t think you have any reason to doubt that the work was done at 175k. By the time the transmission got to you at 221k, it was far more worn and degraded than it was at 100k. Love that you are keeping this car going, but maybe a little perspective: it’s the cheapest Prius, well into its second decade, with high miles and failing batteries. I assume that the transmission is working okay and don’t see why you are claiming dealer shenanigans that happened years ago (most likely did not happen imo) when the real questions are whether you invest more in this aging sled.
The transmission is doing fine. I only changed it this early for peace of mind having seen some people speak about Toyota dealer shenanigans in relation to trans fluid.

Like I said to the previous poster, this car may be only be between 1/2 to 2/3rds of its life. It's running great and has been a fantastic, low maintenance, lost cost, high MPG car. Also, not my car and not my decision. My spouse loves her car and plans to drive it till it dies/needs to be replaced.

Btw, I was not claiming that there were definitely dealership shenanigans, I was only wondering out loud if there could be based on some observations of self and others. Big difference. I do generally practice, or try to, innocent until proven guilty.
 
It's impossible to know if someone did the job they billed you for or not.

Are there not cheaper fluids with dyes which are known to blacken quickly once use begins?
They may have done the job and not used bottled OE ATF. Ha-a compromise on 'dealership suspicion'.
Yeah, that is quite possible. I did ask them after the fact and they said they used Toyota's WS stuff.

If I was going to ever go to a dealer again for this (I'm not), I would install a Fumoto drain plug prior, and take a small sample right after. That would likely clue me in to whether it had been changed at all or not.
 
My spouse has a midd'ish 2010's Prius C. I personally changed the transmission fluid in it at 100k. I remember that the fluid while fairly darkened, was still reddish.

The second time it was changed at 175k, I brought it to the Toyota dealer because it was wintertime and I don't have a heated shop/garage.

What's weird is that I recently changed it again at 221k, and it was black/super dark. It looked worse after 46k miles than it did after the initial 100k. It makes me wonder if the Toyota dealership even changed it? I've read/heard that because Toyota deems the ATF in these cars a lifetime fluid, that it is not uncommon for them to refuse to do this service, or to say they will and don't actually do it.

Anyone have any experience with this or have heard anything about it? I definitely won't be taking it back there ever if I can help it. Same place wanted 5k to change the hybrid battery pack, when I found a guy who used all brand new OEM batteries do it for less than half that. Sure, overhead and all that jazz, but even some other dealerships in the area were like a thousand cheaper.
Keep in mind the Prius C uses a nicad battery pack instead of a Lithium ion battery pack. Maybe this is part of the cost as cadmium is really toxic and I'm sure fairly expensive to recycle.
 
I would drop the pan (is it possible on this one?) for cleaning (clean / add magnets) and then do a drain & fill at every/other engine oil change until it stays clean & clear. Then remove the pan after ~ a year for another cleaning / inspection.
That seems a little overkill seeing as how robustly built and durable these transmissions are and how easy they are on fluid. There are reports of people going 200 to 300k miles on the original fluid. I would never do that, but every other oil change seems excessive.

I have thought about installing a Fumoto drain plug and occasionally checking a small amount, but even that is probably not worth it. Can't say I know the optimal TFCI (just made that up on the spot-transmission fluid change interval) but with everything I've read and experienced so far, it seems like 75 to 100k is reasonable. I do think I should have done the first change earlier than I had.
 
I think it's worth fixing. Vehicles are crazy expensive and that 2010 Toyota is FAR better quality that the 2025's
Yeah, this car has been a dream as far as maintenance, fuel cost savings, etc and as there are reports of people getting to and even past 500k miles, we're going to try to keep it alive as long as possible.
 
The trans oil change may have been forgotten by accident, since they rarely change the fluid? Not a big deal I guess for that transmission, but shows that even charging premium dollars, it doesn't always buy premium service.

As for dealers overcharging for things like batteries, that's their business decision, as big numbers like that can either sell a new car, or make lots of money, or send the customer away. I think dealers sometimes get stuck having to use overpriced parts, or use the full complicated procedure which requires many other new overpriced parts?

Probably finding a knowledgeable independent toyota hybrid specialist would be the best for your battery swap? Or DIY if you can get comfortable with that. I think that era of battery can have individual cells replaced even, a dedicated Prius forum should have all the info you need.
 
They didn't change the oil
Quite possibly.

It's crazy to me if they didn't though, because especially with a lift, this is an easy job. It's not easy for me with ramps and an uneven yard with no paved driveway though. Basically I have to find the most downhill part of my driveway, point the car going down, get on the ramps and approximate even/level. I will say, last time I did it, it did look pretty dang level!
 
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