Transmission warning light or check engine light is on
Delayed or slipping gear shifts
Rough, jerky, or hard shifting
Transmission overheats
Unusual whining, humming, or buzzing noises
Burning smell
Transmission fluid leak under the vehicle
Dark, dirty, or burnt-smelling fluid
Low fluid level on the dipstick
Vehicle hesitates before moving
Gears fail to engage properly
Transmission feels like it is hunting between gears
Dashboard message about transmission or drivetrain issues