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Automatic Transmission Fluid

This is something I’m just curious about . Years ago a friend was looking to buy a used car off a car lot . He asked me to go along to look at cars with him . One car he liked the looks of was a Chrysler product , If I remember correctly a Dodge & we test drove it . It ran well & the transmission shifted fine & seemed to work properly .
When we got back to the lot I checked the transmission fluid & it was brown , about the color of engine oil after a fresh change . It didn’t look dirty or burnt & didn’t smell burnt . I advised him against buying the car because of the color of the transmission fluid & he didn’t buy it but probably would have otherwise . Has there ever been automatic transmission fluid that was brown & supposed to look brown ? I’ll add , it was definitely the transmission fluid I checked & not the engine oil .

I get my transmission fluid exchanged every 30,000 miles. It goes in bright pink. A week later, it’s pinkish-brown. Why? Because exchanging the transmission fluid never gets all of the old stuff out, and then what’s left mixes with the new stuff and gets dulled down right quick.

I don’t think I remember seeing fluid that looked & smelled clean that didn’t have any hint of a red look to it .

I tend to misremember many things. But I think Type F (Ford) ATF was amber verses Dexron (GM) that was red. I don’t remember which color Chryslers used.

Chrysler used ATF3, now ATF4, which are pink/red. Could be the Dodge had the wrong fluid in it, which, according to the site is a major mistake. I think it was reasonable to see a big caution flag in that off-color trans fluid.

Transmission fluid is bright red when it comes out of the container.

Here’s a chart that shows when to service the transmission fluid by it’s color.


The dye used in some automatic transmission fluid is not permanent;


Mopar ATF+4® has exceptional durability. However, the red dye used in ATF+4® is not permanent; as the fluid ages it may become darker or appear brown in color. ATF+4® also has a unique odor that may change with age. With ATF+4® fluid, color and odor are no longer indicators of fluid condition and do not necessarily support a fluid change.

I don’t think that should have been a deal breaker. It was due for an ATF change, but it was not to the point of doing any damage. It would have been a good negotiating point though as the ATF should have been changed ASAP.

I’ve never thought that tranny color was an indicator of if it’s still good. The only indicator I’ve ever used was did it smell burnt.


I have bought quite a few used cars with 20-40K miles on them where I am sure nobody changed the fluid before me and the fluid has always been brown with almost no trace of red in it. I just do 3 drain and refills when I get them and keep doing one drain/refill at around 20K miles after.