2001 C4 Cab 60K miles, Got new clutch at dealer 6 mos/6 k ago. Intermittently about 10% of the time that am at a stop light in neutral, foot off clutch and the clutch pedal vibrates, and it makes a low frequency ticking sound (about 3 times a second tick-tick-tick sound behind the dash) that moves with RPMs. The weird thing is that the slightest depression of the clutch makes it go away, sometimes even after you remove your foot from the pedal/slight depression. I have read other threads and am stumped. I don't know much but am thinking it can't be throw out bearing because that is not loaded in neutral at idle foot off clutch right? and would not dealer have replace throwout bearing any way? dealer said flywheel looked fine 6k ago. I have seen similar problem on another thread fixed by replacing clutch master but cant bring myself to do it without seeing a way a stinkin clutch master could vibrate on its own. I think its just conducting shakes from the clutch - seem more likely? Any idea what this is? guidance appreciated as I am afraid to let it fester. Other than this shaking , the clutch performance is fine.

 

Could be Diaphram Sprins or throwout bearing, do you shif to neutral at lights or just clutch in?

But anyway, since you just had the clutch worked on my best guess would be misalignment between the clutch assembly and the flywheel. This is where I would start and I would start by having the people who did the check the alignment. This could be caused by worn transmission mounts and or worn engine mounts.

 

Always in neutral foot off clutch at lights - can't handle the extended leg press

 

Have the alignment checked.