linetrash75

Got a growling sound from under the truck with clutch pedal released, goes away when I press the clutch. Is this the throw out bearing or is it on the input shaft. It seems too loud to be in the tranny,seems more out in the open.
Thanks Jed

ericg

Sounds like the throwout bearing to me, you can gently start pushing the clutch in and if the noise goes a way before the tranny stops turning then it's defenatley the bearing

bill50cal

wrong. the throw out bearing is in high load with clutch pedal depressed and that is when it will make noise. I would start looking at stuff like input shaft bearing.

ericg

Not sure how the input shaft would bearing would make noise with the clutch depressed as the trans wouldn't be turning. Unless I misunderstood something here

bill50cal

he said it was making noise with pedal released so no pressure on throw out bearing and input shaft turning. with pedal pushed down and clutch released the load is on throw out bearing and nothing in trans is turning. now IF the pressure plate fingers is uneven and making the throw out bearing rattle on the front bearing retainer that is another issue but all of the above will require the trans to come out.

bill50cal

push down part way on the pedal ( but not enough to release the clutch ) does the noise go away?? if so I would look at the clutch, if you have to fully release the clutch for the noise to go away than look at the trans.

linetrash75

Thanks for your help guys. The noise goes away with the slights of pressure on the clutch pedal. leading ne to beleive it is clutch related.

Jed

totalloser

When you push the clutch, the throwout bearing puts load on the fingers of the pressure plate pulling it back from the flywheel allowing the disc to turn at a different rate than the flywheel.

The flywheel is turning at engine speed, the input shaft is attached by splines to the clutch disc, so the part connecting the spinning flywheel to the stationary disc is the pilot bearing.

Having said that, sometimes a bad throwout bearing is noisy as it drags on the clutch for a handful of possible reasons and quiets down when you put pressure on it. Usually in this case the noise disappears when you just barely push on the clutch. To get pilot bearing noise, you need to FULLY disengage to the clutch.

Same with transmission noises. The transmission doesn't know how hard the clutch is engaged, just whether it's turning or not. So if light application of the clutch pedal (not enough to disengage it) changes the noise, you can eliminate pilot bearing and transmission.

There are so many random failures that can take place in a clutch, sometimes it's hard to nail down, though. As long as you can eliminate a hydraulic problem (clutch hydraulics) and a transmission problem, it doesn't really matter much because the transmission will need to be pulled to fix it. Usually once you get in there, the problem is pretty obvious, but even if not, all the potential problem parts *should* get replaced anyhow.