ATF Getting Dark after Changed 13K Ago
 

Hi,

My 1989 Camry with 155k miles and an automatic transmission is doing fine (well it shifts a little rough but that's probably to be expected on a 28 year-old car).

Today, I checked my automatic transmission fluid and it's not bright pink. Rather, it's more dull red and almost brown. I have a poor sense of smell, so I can't tell if it's burnt. Is that color normal after I flushed the tranny fluid 13k ago and it was nice and pink? 13k ago, my radiator blew, so I changed the radiator and tranny line hoses and dropped the pan, replacing the filter. I also alternated idling the engine and draining the pan until the ATF was pink.

Today, out of abundance of caution, I drained 2.5 quarts from the pan drain plug and replaced it with new ATF. Should I complete a flush, or wait until the 25K mark?

Thanks!

In the 13K change, what procedure was used to change ("flush") the fluid from the trans?

Draining the trans pan and refilling just mixes old fluid with new.

Trans color alone is not an indication of fluid condition.

If not hot rodding or pulling a trailer, conventional fluid should last 25K miles.

Thanks. I can't easily remove the transmission line to the radiator, so I have to drain the pan, then add replacement ATF through the dipstick, run the engine, then repeat.

I don't hot rod or tow, but I drive on somewhat steep hills, necessitating my downshifting the transmission to "2". Would that require more frequent ATF changes, or just every 25k?

What else, besides transmission fluid color, can I use to determine the condition of the fluid?

Thanks!

It is not possible to obtain 100% new fluid in the trans by doing pan drains and refills. Most of the fluid (2/3) is in the torque converter and does not drain out by gravity. It needs to be forced out during a "flush."

If wanting to "flush" the trans. Disconnect trans fluid output hose from the radiator at the trans tube. Start engine and allow fluid in pan to pump out. Stop after about 2 quarts, then refill pan and repeat until clean fluid.

One can take a few drops of trans fluid and place on a white paper towel. Let the fluid be absorbed then inspect the area. Compare color to that in one of the color charts in the link below:

https://www.google.com/search?q=tran...jU0R-qZQEBlqM:

Trans fluid odor can be used but fluid brands have different odors. Having a "burnt" smell is supposed to indicate worn fluid but this can be subjective.

The issue with trans fluid is heat. Fluid life is directly related to how hot it got.

Without a trans fluid temp gauge or lab testing of the fluid, my two cents is 25K is adequate. Much more adequate then 99% of what most car owners do, which is pretty much never changing the fluid.

Thanks!

Based upon the color chart, it looked like mostly the burgundy red/normal new fluid and a little of the third/dark fluid.

Is the trans fluid output hose the higher or lower hose at the radiator?

Thanks

Can't remember.

Thought it was the tube on trans closest to the drivers side.

Thanks. I'll have to double check, but I thought that there was an upper and a lower line.