What symptom would suggest that a vehicle needs a transmission fluid change?

A symptom indicating that a vehicle needs a transmission fluid change is often delayed or rough shifting. When the transmission fluid is low, old, or contaminated, it can't provide adequate lubrication, hydraulic pressure, or cooling. This can lead to the transmission not engaging or disengaging smoothly, causing a noticeable delay when shifting gears or rough transitions between gears. Proper transmission function relies on clean, effective fluid, and any abnormal shifting behaviors are a clear sign that maintenance is required. This emphasizes the importance of regular checks on transmission fluid, as timely changes can help prevent more serious transmission issues.