What is typically a common symptom of a failing slave cylinder?

A common symptom of a failing slave cylinder is indeed the inability to shift gears. The slave cylinder is a crucial component of the hydraulic clutch system, which operates by transmitting force from the clutch pedal to the clutch assembly. When the slave cylinder fails, it may not apply sufficient pressure to disengage the clutch properly. This can lead to difficulties in shifting gears, as the clutch may not fully disengage, causing the driver to experience resistance when trying to change gears or even making it impossible to shift at all.

The other symptoms listed do not relate directly to the function of the slave cylinder. Increased clutch pedal resistance is more indicative of issues within the clutch assembly or the master cylinder. Overheating engine symptoms are generally related to cooling system problems or engine issues and not linked to the operation of the slave cylinder. Vibration during acceleration is often associated with drivetrain or suspension issues rather than clutch hydraulic problems. Thus, the inability to shift gears serves as the key indicator of a failing slave cylinder.