In vehicles with hydraulic release systems, the release bearing is in constant contact with the clutch diaphragm fingers. A squealing noise on engagement can result when the release bearing and clutch rotate at different speeds. If the noise stops after approximately five minutes, replace the slave cylinder with part # CSC232. If the noise continues after the vehicle is warm, the cause is probably the release bearing and/or pilot bearing. To determine which bearing is the source of the problem, set the parking brake, put the vehicle in neutral and start the engine. If it’s the release bearing, you’ll hear chirping which gets louder when you slowly depress the clutch pedal. If it’s the pilot bearing, you’ll hear squealing when you depress and hold the pedal.

For additional information, refer to Toyota bulletin #032.