Engine revs rise without a matching increase in speed
RPMs flare between gear changes
Delayed or harsh shifting
Slipping sensation during acceleration
Transmission hesitates before engaging
Vehicle struggles to maintain speed on hills
Burning smell from transmission fluid
Transmission fluid is low, dark, or dirty
Check engine light or transmission warning light is on
Unusual whining, buzzing, or grinding noises
Gear changes feel inconsistent or unpredictable
Vehicle may not move immediately when shifted into drive or reverse