My daughters low mileage RAV4 transmission fluid recently turned black. I check the fluid once a month, went from pink and sweet normal odor to black and no odor. No over heating, no codes, no driveability problems. We took it to a local shop and he is puzzled. The computer is not showing any overheating and the fluid does not smell burned. The shop drained and refilled the fluid, asked us to come back in 200 miles and he will drain again.(no charge for the second drain/refill)
Anybody have any ideas on what might be happening?
The transmission fluid is oxidized.
That’s why it’s black.
https://engineneeds.com/why-does-transmission-oil-turn-black/
Tester
It’s been my experience that Toyota factory trans fluid tends to turn dark quite early, without any burned smell or texture. Personally I think it’s just a characteristic of the factory fill fluid. I don’t see Toyota transmissions fail any sooner than any others. On the contrary, I think they’re pretty durable.
Changing it can’t hurt, but I wouldn’t lose any sleep over it.
In my environment, World Standard fluid is black after 100,000 miles of hot city driving, discolored after 50,000 miles.
Automatic transmission fluid was significantly improved 25 years ago, modern fluids may not have the same appearance as traditional fluids.
While not specifically about World Standard fluid, here is a note from an old Chrysler service bulletin regarding long life fluid:
FLUID COLOR
Mopar ATF+4(R) has exceptional durability. However, the red dye used in ATF+4(R) is not permanent; as the fluid ages it may become darker or appear brown in color. ATF+4(R) also has a unique odor that may change with age. With ATF+4(R) fluid, color and odor are no longer indicators of fluid condition and do not necessarily support a fluid change.
Although you only have 46K miles on the vehicle, if I did the math right, you have 168 months on the OEM ATF (if never serviced), you should be doing a drain and fill about ever 60Kmiles OR ever 72 months which ever comes 1st as a rule of thumb… So you should have already done a drain and fill for the 2nd time 12 months ago…
Like said above, it’s a Toyota, don’t loose to much sleep over it…
Besides that, if something internally had happened to cause any concern, you would have made an entirely different post about your transmission failing…
That’s a strange one. The fact that it turned black without the usual burnt smell or transmission issues would have me scratching my head too. I had something somewhat similar on a used SUV bought through a Copart auction a few years back. The transmission fluid looked way darker than it should have for the mileage, but the transmission shifted perfectly and never threw a code. In my case, multimple drain-and-fills gradually cleaned things up and the transmission ended up being fine. Your mechanic’s plan sounds reasonable. I’d be curious to see what the fluid looks like after another 200 miles. If it darkens again quickly, a fluid analysis might be worth the small cost just to see what’s actually in it.
Don’t panic - what you are seeing is actually a well-known characteristic of Toyota’s factory World Standard (WS) transmission fluid. This specific fluid is notorious for turning dark brown or completely black relatively early in its lifespan. Because there is no burned odor, no metallic flakes, and no high-temperature codes on the computer, the fluid has simply oxidized and suspended normal clutch break-in dust rather than suffered a mechanical failure.
Your local mechanic is handling this perfectly. A standard drain and fill only removes about 35% of the fluid at a time because the rest stays trapped in the torque converter; doing a second service after 200 miles allows the new fluid to mix thoroughly and safely clean the system. Just ensure they refill it with genuine Toyota WS fluid (or a high-quality equivalent like Valvoline MaxLife ATF), and your daughter’s RAV4 should be perfectly fine to drive.
This was surprising to read. They must be charging enough to cover both services at the initial service or how do they make any money on it?
The price is $309 which I think is very reasonable. The shop has a great reputation for being fair and competent.
You definitely won’t hurt anything by changing the fluid. I see many suggest AGAINST the flushes as they can dislodge crud that would otherwise stay in place for the life of the transmission and likely not cause issues. Every shop around here suggests against a pressure flush like in the video. They do mention removing the transmission cooler line and continually adding fresh fluid until the fresh starts to come out the cooler line looking clean. Of course you have to be very careful to not let the transmission suck air so it might be a good idea to have someone in the car to kill the engine when you yell that the fluid is coming out clean.
