Help with clutch noise/vibration

[NikP]

I have a noise that I need help to diagnose. It happens when i push in the clutch and rev the engine. It feels like a spinning type vibration and it can be felt in the shifter. The vibration seems to lag the rpm. I let out the clutch and it goes away. Happens also when shifting up or down so I'm pretty confident it's clutch related.

My guess is throw out bearing but I can't believe one would fail after 2400 miles. Everything in clutch was new and flywheel was turned. Seems to be adjusted correctly because it doesn't turn when at rest and engages okay.

Any ideas on how to diagnose for sure? I've been under the car with the noise created but can't really see anything. I hear it in the clutch area. I hate to drop the transmission without knowing more.

It's SBC with Toyota splined disc mated to low profile pressure plate. TO bearing was new from AA.


Thanks for the help

 

[ingomar]

As you suspect, any noise/vibration only present when the clutch is depressed is usually the throwout. Remove the dust cover, back off the linkage, and try to feel by hand if the bearing is rough or discolored. How much pedal free-play have you been running? And is this noise just now becoming noticeable (was it quiet when new?)

 

[Cdaniel]

+1 on throwout bearing. Or, what condition was the nose piece of the trans where the bearing rides? Any slop that would allow the bearing to not stay true or perpendicular to the clutch? Or allow the inner race to spin on it?

 

[FJ40WY]

It could be the pilot bearing or bushing. did you lubricate and replace with new when you did the clutch?I have a SBF that has 12,000 miles on it with all new clutch components. it has a noise when engaging the clutch that most would insist is the TO bearing. my sound is worse when cold. the sound changes with the difference between trans shaft speed versus engine speed. mine doesn't effect shift quality and did it since the rebuild so i have no reason to try to fix it.

 

[NikP]

I noticed a slight squeal some time ago when it was cold but it would go away pretty quickly. I haven't heard the squeal much, but lately have noticed the vibration & such.

The TO bearing looks brand new. I spin it by hand and it doesn't feel bad but that's probably no indication since it happens at higher RPM's. Free play was set according to the manual and the TO bearing has maybe 1/16-1/8 of play before it comes in contact with the pressure plate fingers.

As you suspect, any noise/vibration only present when the clutch is depressed is usually the throwout. Remove the dust cover, back off the linkage, and try to feel by hand if the bearing is rough or discolored. How much pedal free-play have you been running? And is this noise just now becoming noticeable (was it quiet when new?)

 

[NikP]

Yep, all new including the pilot bearing. When my vibration occurs, it plays havoc with the shifting as it resonates through the shift lever. I'll probably tear it apart so see what's the deal as much as I hate to.

Wouldn't a pilot bearing noise exist even with the engine in neutral?

It could be the pilot bearing or bushing. did you lubricate and replace with new when you did the clutch?I have a SBF that has 12,000 miles on it with all new clutch components. it has a noise when engaging the clutch that most would insist is the TO bearing. my sound is worse when cold. the sound changes with the difference between trans shaft speed versus engine speed. mine doesn't effect shift quality and did it since the rebuild so i have no reason to try to fix it.

 

[FJ40WY]

with mine the noise happens when i push in the clutch and while i shift into gear. It is when the transmission input shaft slows to a stop because it is in gear while the engine idles (large difference in rpm's between flywheel and input shaft.) In upshifting there is no noticable noise/vibration. when downshifting 4/3 3/2 you notice the vibration because of the input shaft spinning faster than the engine until the pedal is released again.

Pilot bearing noises only exist when the clutch is pressed and there is a difference in rpm's between input shaft and flywheel. A throwout bearing could make constant noise if it is in contact with the pressure plate fingers. EG: 90's chevrolet trucks had hydraulic slave cylinders that were in constant contact with the throwout bearing which made for a much shorter life and interesting noises as the bearing gave up the ghost. The hotshot truck I used to drive went through 5 throwout bearings and still had the original clutch disk when we traded the truck at 250,000 miles.
Hopefully this all makes sense and aids you in troubleshooting your noise