Transmission warning light or check engine light is on
Delayed shifting or hard shifting
Slipping between gears
Transmission overheating
Unusual whining, humming, or buzzing noises
Grinding or jerking during gear changes
Transmission fluid leaks under the vehicle
Dark, burnt-smelling, or dirty transmission fluid
Low fluid level on the dipstick
Vehicle hesitates before moving
Trouble engaging reverse or drive
Transmission fluid foaming or bubbling on the dipstick
Dashboard message indicating transmission issue