Restart it and if will go anther few miles. It takes all gears fine. My transmission fluid is brown
My car has 19300 miles.
My car has an automatic transmission.
I see your note about the color of the transmission fluid, but is the fluid level correct too? Dark or burned fluid along with a low level can cause the transmission to slip and if the fluid smells burned there may be a lot of internal wear to the point where the unit needs to be overhauled. The best place to go for a proper diagnosis would be your local dealer or transmission repair facility where transmission teardown can be performed if necessary to get to the bottom of your concerns.