If it is transmission fluid, you will need to replace the radiator. There will be 2 transmission cooling lines going to the radiator to cool the transmission. If your radiator is old, chances are it has rotted and the transmission fluid is leaking into radiator. This needs immediate attention to keep from destroying the tranny
I have same problem,brown radiator fluid with pink 50/50.I flushed radiator,put geen 50/50 but looks brown with green,it can't be the tranny its a new trans!I just fixed the radiator drove to work and checked again to find it brown again.I checked motor oil dipstick-its clean with no water,I checked trans dip stick to see if theres water in trans but no theres no sign of damage so its the radiator that needs to be replaced acording to a mechanic,theres a line that runs to radiator in which theres a leak allowing tanny fluid to enter into radiator.replace radiator,get trans flush and flush out the motor block.sorry youll have to spend some cash
New radiator but trans. Fluid in radiator what does this mean
I don't think it is tranny fluid unless someone put it in there to be mean. If your fluid is green then it isn't tranny fluid. Tranny fluid is red. Hope this helps.