Too late? Transmission Fluid Change 170k miles, New Prius Owner

Hi Everyone!

I looked for a similar forum to my question and couldn't find an answer so I decided to open a forum.

TLDR: Bought my first Prius! 2010 with 169,000 miles on it, I'm not 100% sure, but I don't think transmission fluid has ever been changed. Should I have it changed? Or just live with the transmission fluid as is, and maybe get a used car warranty incase the transmission breaks?

Previous owner changed engine oil every 3,000 miles, car seems to be in pretty good condition, and has a new water pump. My only concern was the battery since it hasn't been changed, but it isn't issuing any codes. My engine seized on my last car so I got the best prius I could as quickly as possible. Under more optimal circumstances I would've taken my time and waited for the best one to pull the trigger on. Paid $7,850 before tax & fees. CarFax and everything looked great, but after I bought the car I realized I didn't look to see if there had been transmission fluid changes. To my dismay when I looked back at the service history it doesn't look like the transmission fluid has ever been changed which seems weird for an owner who would change the engine oil every 3,000 miles. I'll try calling the shops who maintained the prius to see if they have any record of it, but if they had a record they probably would've put it into the carfax along with the oil changes.

Quick note on the battery, I'm averaging roughly 42mpg (mostly city mileage, uber eats) trying to mostly drive in the eco "zone" but sometimes I have to push it into power since it has trouble accelerating up hills or in pinch situations. The battery seems to charge and discharge more quickly than it should. I've read about the Project Lithium batteries (which would be my preference) but they're out of stock. But maybe I don't have to change the battery yet, maybe I just do some reconditioning on it. I'm not sure, I'm also a bit wary about switching to Lithium since it's less "tested" than NiMH. Not 100% what to do there, but I also need to do more research. I think the primary concern right now should be the transmission. Since I am driving Uber Eats in the Dallas heat, I know I'm putting a lot more strain on my battery than a "normal" user... so it still is definitely something I will have to handle soon.

Thanks for all of your help in advance! I already freaking LOVE my prius and stoked to be a prius owner! I was nervous at first, mostly about the seats, since my mom had a Gen2 and I only remember the seats being horribly uncomfortable, but I think they fixed that issue in Gen3!

 

Honestly never even heard about the EGR circuit until now. I'll have to look into it more, I took it for a pre-purchase vehicle inspection and the mechanic said everything looked good. The only warning light that's on is the TPMS, I've filled the tires once, and then went back to check a couple times and they were fine, so I'll need to get that checked out. Had a friend said take it to a Toyota dealership and they'll recalibrate the sensors for free, I also think Discount Tire would probably do this. Hoping I don't have to replace those sensors.

The reason I was asking is because I've heard that if you don't replace the transmission fluid on time, sometimes it's better to just never change it if it's gone too many miles without being changed in the past.

The water pump was changed at 155,000 miles so I'm guessing all the coolant had to be replaced then as well. Looking at the CarFax service history doesn't show coolant replaced anywhere else though. I know CarFax service history isn't always comprehensive since a lot of shops don't report so some of this is guess work. I'll have to look into how to check EGR status. History also says at 165k miles engine oil/fluid leak checked... Don't know what that was though, the inspection I had done said there were no leaks so maybe it was fixed. I saw in another forum an anecdote about a Taxi company with a ton of prii where they never changed transmission fluid and also never had any transmissions breakdown with 300k+ miles on their prii.

 

Thank you! Awesome, sounds like I shouldn't be concerned either way. I was also worried that maybe the fluid had been changed but they used the wrong fluid, I've seen a few posts about using the wrong (not Toyota branded) transmission fluid could be bad for it so I was also a bit worried about that. Sounds like it's kind of optional either way, so not the most urgent thing I need to work on.

Thank you! The transaxle fluid is new to me, so I'll check on that for sure. A couple people also mentioned the EGR so I'll also look at that. I'm hoping these can be done at home, because I don't know how to find a good hybrid mechanic since everything seems a lot different than a normal car, and I don't really want to pay Toyota Dealership prices. Checking the brakes was on my list, I've heard a couple minor screeches but I don't know if they're the brakes or not. I had a pre-purchase vehicle inspection done, I assumed he looked at the brakes but now that I think about it I didn't mention it and neither did he. I'll add checking the brake fluid. I think I also need to get the tire sensors reset since the TPMS won't go off, even after I fill the tires. Other than that I think I'll be good. I do want to get the windows tinted partially for privacy but partially because it's really hot in Dallas right now... Thanks again for your help!

 

That's good to know, thank you! There are a couple other things that I was a bit concerned I didn't see on there, like brake replacements but I don't think Prius have "normal" brakes so I wouldn't have a clue.

 

I just realized that the transaxle is the same thing as the transmission...

I'm going to change the transmission fluid, since it seems like even if it has never been changed it's not similar to other transmissions that I might do more harm than good. Brakes are down to 4mm so when I change those in the next month or so I'll also have them change the brake fluid. I'll check the EGR system to see if it needs maintenance.

I've put about 1500 miles on my Prius already, and I know I'm definitely going to have a Prius for life. Because of work I might need a truck or off-road capable vehicle as well, but I'll always have a Prius in the family, my favorite car I've ever had.

I'm still trying to decide if I go Lithium or just do battery reconditioning, it's hot as hell in Dallas and I notice I lose about 20% MPG (from 47-48 down to about 40) just trying to keep the car cool enough, and even with that I notice a huge difference in battery performance (much weaker acceleration, and dies within a minute) when it's hot as balls out vs at night. I know Lithium has better performance when it's really hot, and also can blast A/C for a half hour without ICE turning on (at least from what I've read) - but It's a pricier upgrade so I might just ride out the summer and think about it next year. I'm expecting/hoping to be able to put 130k+ (and get over 300k) miles on this Prius, and don't really want to buy a Lithium battery if I'm not going to get the full life out of it. I know they guarantee 30k or something, but I can't find info about how many miles the Lithium batteries last. Definitely don't want to have to replace the battery twice, but also don't want to replace it too late and not get the full "life" out of the battery before I have to get rid of it. Or maybe I just keep both batteries and when it's time to move to another Prius, but the NiMH back in, and keep the Lithium for the next car. Idk, kinda just thinking out loud.

Doesn't help that my car is black, and doesn't have any tint. I'm thinking that's another thing I'll do. Also the paint is in the early stages of sun damage, there's a few spots about the size of an iphone where the clear coat is bubbling off, so either I sand and respray some 2k, or I just wrap it white which is what I think I'll do since that'll help with the Dallas sun. Headlights are getting pretty blurry so I'll get that done too.