rebuilt or replaced.
In summary, on transmissions where the fluid is dark brown or black, proceed
with caution. Drop the pan and inspect for wear material. If wear material is
evident inside the unit, just change the fluid in the pan, install a new filter, close
it up, and drive it. If the fluid is a milky color (like a strawberry milkshake) then
there’s moisture in the unit usually due to a ruptured oil cooler in the radiator.
This is not good. When engine coolant mixes with transmission fluid, the
transmission usually fails in short order because the water and engine coolant
compromise the rubber seals. If this happens, the transmission usually has to be
rebuilt or replaced.
Consistency
The fluid should be slippery and smooth to the touch. A gritty feeling usually
means that there’s wear material in the pan and that the unit should be opened up
and inspected.
Smell
The fluid should smell like oil. A burnt smell indicates transmission overheating.
Usually when the fluid is burnt it’s darker in color. Follow service procedures as
outlined in the color section above for overheated transmissions.