If your vehicle is showing high-pitched squeal when pressing the clutch pedal, here are the most likely causes and the parts you'll need to fix each one.
The release bearing presses against the spinning clutch pressure plate when you step on the pedal. If its internal lubrication dries up or the bearings fail, it will emit a high-pitched squeal under load.
The pilot bearing supports the transmission input shaft in the back of the crankshaft. When the clutch pedal is pressed, the engine and transmission spin at different speeds, causing a dry or worn pilot bearing to squeal.
If the transmission input shaft sleeve (snout) wasn't properly lubricated during a recent clutch installation, the release bearing can bind and squeak or squeal as it slides forward.
The metal fingers on the pressure plate can wear unevenly over time. When the release bearing contacts these deeply grooved fingers, it can create a metal-on-metal squealing noise.
Pressing the clutch pushes the crankshaft forward. If the engine's thrust bearings are severely worn, the crankshaft shifts too far, causing internal metal-on-metal scraping or squealing.