When transmission fluid is low, the transmission tends to jerk or slip when changing gears. The vehicle may also speed to high revolutions per minute while in neutral or without the vehicle speeding up or spontaneously slip out of gear. A burning smell is another sign that transmission fluid may be low.
A vehicle with a manual transmission may have difficulty going into gear when transmission fluid is low. It may also pop out of gear, with the gearshift sliding back to the neutral position without warning.
A transmission fluid leak is typically a sign that there is a problem with the transmission. Transmission fluid is red, translucent and smells slightly sweet. With an automatic transmission car, it is possible to check the transmission fluid dipstick to determine the amount of leakage. If the fluid level is slightly low, it is likely okay to drive to a garage to have the fluid level and the leak checked. If the fluid level is significantly low or if the fluid is dark or has a burnt smell, the car should be towed to a garage. Transmission fluid is not used up during driving, so any dip in the fluid level indicates a leak is present and must be repaired as quickly as possible.