If your vehicle is showing grinding noise when shifting gears, here are the most likely causes and the parts you'll need to fix each one.
The clutch friction disc, pressure plate, or release bearing is worn out, preventing the engine from fully disconnecting from the transmission during shifts.
Old, contaminated, or low transmission fluid fails to properly lubricate the gears and synchronizers, leading to harsh, grinding shifts.
A leak or internal seal failure in the clutch master or slave cylinder prevents adequate hydraulic pressure, meaning the clutch pedal cannot fully disengage the clutch.
Worn or missing bushings in the shift linkage create excessive play, preventing the shifter from pushing the transmission fully into gear.
If the clutch hydraulic system was recently opened or replaced and not bled properly, trapped air will compress instead of moving the clutch fork, causing grinding.
The internal brass synchronizer rings that match gear speeds before engagement are worn out. This usually causes grinding in one or two specific gears rather than all of them.