Drive the Honda Civic for around 10 minutes, shifting into each gear to allow the oil to circulate throughout the system. Park the car on level ground, and open the hood.
With the engine turned off, locate the dipstick on the lower-left side of the engine on top of the transmission chamber. Pull it out slowly, and check the level and color of the fluid.
A fluid level close to the full mark indicates ample fluid in the system. If the color looks blackened or the fluid seems marshy, it's time to change the transmission oil.