pvkn1ght

Searched'n'read many a threads on this.

My car has developed a shake/vibration as the clutch is let out, an unwelcome partner to the already annoying t56 throwout bearing rattle. It shakes the rear hatch pretty good with passengers or at an uphill stop/go. Who votes for a throwout bearing on it's way out? Pilot bearing?

Can the throwout and pilot bearings be inspected visually underneath the car? Also, can either of the bearings be replaced without replacing the clutch as well??

Thanks a lot - Brian

NOTE: I do not literally know what either of these parts do - someone enlighten me please

ZDriver96

Pilot bushing/bearing- (always use a bushing not the bearing).. Im a bit fuzzy on the pilot bushing.. but if i remember right.. it sits inbetween/infront ofe the Circular rear main seal/ center of the flywheel. Helps keep the flywheel and input shaft centered as they rotate.
The throwout bearing sits in the clutch pressure plate. It allows the clutch connects with a shift fork that will allow the clutch to disengage when u press your foot on the clutch.
You have to yank the tranny to see them..
I'd replace both at the same time. Pilot bushing is cheap.. TO bearing is not exactly.
You can kinda see the shift fork.. It has a line running into the drivers side bellhousing, held in by 2 bolts..

Just change both.. Thats how i do it... i still have a weird tranny problem... i rebuilt the tranny, changed the to bearing and it still kinda does it... its alittle better but some weird sounds still come out at certain times/rpms.. pissing me off.. I think im just going to yank the whole clutch and tranny for a brand new T56 and mccleod street twin. Im **** about noises and stuff.

pvkn1ght

thanks

it's not so much the noises that bother me - but it's the shudder/shake through the car (shakes the rear hatch even) when the clutch is let out, right as the gear engages.

anyone??

AL SS590 M6

That sounds like plain old fashioned clutch chatter. The clutch is probably on it's last legs. It's caused by the disc grabbing and slipping, grabbing and slipping. If you let the clutch out faster with a little more gas it might not do it as bad. Of course you might squawk the tires too

pvkn1ght

... doesn't clutch chatter refer to a sound only? yes i know there is the usual t56 growl that goes away when you engage at higher rpm's or by releasing the clutch faster.

the clutch on the car is not slipping as far as i or my mechanic can tell | i'm referring to a shudder/shake through the car that goes along with the clutch chatter as the gear engages.

please help | thanks | brian

chevroletfreak

It is the pilot bushing/bearing.

Anytime the clutch pedal is pressed in, the input shaft of the trans is spinning inside of the pilot bushing/bearing. If the bushing/bearing has failed, the input shaft can get gouged and cause it to vibrate.

If it was a pilot bearing, the pins have most likely gouged the input shaft requiring its replacement.

If it was a bushing then you will most likely be able to replace the bushing itself with a new one.

My advise is to always replace the bushing/bearing with a bushing. The bearings will fail earlier and cause more damage with it.

If you have any ?'s I have dealt with this. Just let me know.

pvkn1ght

PM sent - thanks - anyone else with a diagnosis or advice?

Brian

AL SS590 M6

No. It is as I described. The car jiggling and shaking right at the point of engagement.

TW95Z

My vote would agree with AL SS590 M6. The shudder you feel in the car as you let out the clutch, especially loaded or on a hill, makes me think your clutch disk is worn out.

Here's a picture of the clutch pilot bearing in this case
http://www.pharmacy.arizona.edu/staf...lotbearing.jpg

it is in the center of the crank shaft. Your transmission input shaft goes inside. So when you are sitting at a stop, your engine is running, your crank shaft is turning and the clutch pilot bearing/bushing is turning around your transmission input shaft which isn't moving. I've not had a failed pilot bushing or bearing so I don't know for sure, but at a stop is where I would expect to hear/feel a problem if the pilot bushing had failed. Once you have let the clutch out the crank shaft, pilot bushing, and input shaft are all turning at the same speed.

The throwout bearing failures I've experienced (in other vehicles) have involved a
noise/shudder in the pedal only/increased pedal stiffness pressing IN and also when releasing the pedal.

pvkn1ght

thanks for all the help!

i thought a slipping clutch would cause the engine to rev before the car accelerates when i punch the gas? it's not doing this...

could it still be the clutch? either way i gotta take it all apart to determine if it's clutch, t.o.bearing or pilot bearing right?

thanks again - this board rocks - Brian

TW95Z

True, but yours is chattering which is a rapid grab-slip-grab vs complete slip vs the normal smooth transition from slip to grab.

Two other questions -
(1) does the chatter stop when the clutch is fully engaged and you are just driving down the road? If Yes then suspect the clutch.

(2) Please don't take offense at this but we have to rule out the human factor. Have you been able to start on a hill with a backseat full of passengers without the chattering in the past. If No then the solution is a change in driving style as suggested before, let the clutch out faster with more gas.

Yep you'll need to take it apart to inspect everything. If you replace the clutch disk you will also replace the pressure plate and throwout bearing (usually all comes as a kit). Most also have the flywheel resurfaced, and while you're there replace the clutch pilot bearing/bushing and rear main seal (don't want an oil leak after doing all this).

Hope this helps,

GMH94Z28

I know this is an old post but did you ever get this resolved? I am having the same issue when I am engaging the clutch in first it shakes the whole car. Thanks

Z94SLEEPER

What was the found cause of the shaking?

I was driving the other day and missed a gear. (wouldn't go in when shifting somewhat fast) Afterwards, the clutch pedal shakes at idle, there's a vibration in the shifter and the car shakes when going into 1st gear then smooths out with the other gears. I didn't drive it much more as I was close to home. (1/4 mile) Did the clutch or something else associated with the clutch let go? I have had this clutch for a long time with much abuse on it. Still seemed to hold fine when I did get on it.

DAVE00

Probably a bad clutch or pilot bearing. I had the same issue a few months back and finally decided to pull the tranny and take a look. What I found was the clutch (centerforce dual fric) had 4 of the 9 clutch pads missing on the flywheel side and it was causing a balance issue and ruined the pilot bearing. Replaced clutch, pilot bearing and throwout bearing (part of centerforce dual fric) and better than new. Hasn't shaked since, except if you consider loabing at idle shaking (LOL). My suggestion is get that tranny off and you will probably see what the problem is, if you do find out it is the clutch or anything else replace that pilot bearing while you have it off as it's a cheap part and better to do it now. Good luck.

Z94SLEEPER

Thanks for your input!
I'll have to tear it down to see exactly has been broken. Is it hard to get the bushing out? I had a shop install it last time.
Also, did you just buy the clutch, pilot bearing and throwout bearing? Did you have to buy the whole kit or just the disk? I will have to look at the flywheel as well and hope it's fine however I've put some hard miles on the clutch....

Thanks,
Eric