The TDI clutch is pretty sturdy. The most common reason for replacement is because it slips or it’s broken. Clutch slip is when you notice the rpm move up without translating into forward motion. If you notice the rpm flutter and go up with speed, you are slipping the flywheel and clutch. The best way to avoid large torque spikes is to apply power smoothly instead of mashing the go-pedal down. There could also be glazing or oil leaking onto the clutch from the rear main seal which lowers the coefficient of friction.

If the clutch is simply not working, it could be a few things. If the clutch pedal goes to the floor or the shifter won’t go into gear, it could be a problem with the clutch hydraulic system or shifter and not the actual clutch. The clutch fork/bearing can fail and cause poor clutch release/shifting. If quickly pumping the clutch pedal or bleeding the hydraulic system makes a difference, the problem is most likely with the master, slave cylinder, or flexplates hydraulic lines. The slave normally goes first because water and contaminants settle at the low spot which is the slave cylinder. Noise could also be the motor mounts, flywheel, or a loose slave cylinder. If the noise is growling only when the clutch pedal is pressed enough to make the release bearing touch the pressure plate, the sound is probably coming from the release bearing.

How long can a clutch last? In theory, the clutch disk could last forever if you perfectly rev match every shift. However, the pressure plate springs that clamp the clutch disk can get worn. Oil can leak onto the clutch. The TDI has a pretty reliable flywheel the movie clutch when power is left at stock power levels. Most pressure plate springs actually increase the amount of holding force as the clutch disk wears. However, if it passes the optimum point, holding force decreases. Glazing or oil on the clutch surfaces can further reduce holding force.