Throwout Bearing???

[cadillac531]

Armed with my new fuel pumps and tires, I took the Beast for a little trip out of town last weekend. She ran like a champ, through the rain, and up the hills and mountains with the AC on and the cruise on, it pulled down 23.2 mpg. I was pretty happy, as this makes the ZR my most fuel efficient vehicle :)

Anyway, when I left my folks' house to come back home, the trans made a high pitched bearing-like sound just as the clutch engaged. It did it as I would engage reverse and as I would engage first. I took it around the block before heading on back, and when everything warmed up, the sound went away and didn't come back.

I started the car again today and it gave me the same sounds, I rocked the car front and back with the clutch and after the third time of doing this, the sound stopped and the clutch engaged quietly like usual.

Can anyone describe to me the sound a throwout bearing makes? The trans shifts fine, and there are not any other audible sounds other than the ones a ZF usually makes.

Thanks.

[QB93Z]

The sound you describe could be the pilot bearing. It is sometimes hard to differentiate between pilot bearing and throw out bearing noise.

In my most recent experience, the pilot bearing gave the symptoms you have. The noise would go away after the first few clutch operations. A bad throw out bearing doesn't usually get quieter.

Either way, the transmission and clutch need to be removed.

Jim

[GOLDCYLON]

#2 on the pilot bearing. Throw out bearing noise does not go away. Kinda like fidanza flywheel noise that only goes away when you enguage the clutch or while cruising

[cadillac531]

Thanks for the replies guys. I will drop the trans and get this all fixed up.

[XfireZ51]

Use the brass bearing, not the needle bearing pilot. Fewer parts to go bad.

[cadillac531]

Use the brass bearing, not the needle bearing pilot. Fewer parts to go bad.

Thanks for the reply. In a previous post I found, Mark Haibeck suggested this pilot bearing gm pn14061685 saying it won't come loose. Do you happen to have a part number for the brass one you suggest?

Thanks.

[WVZR-1]

Thanks for the reply. In a previous post I found, Mark Haibeck suggested this pilot bearing gm pn14061685 saying it won't come loose. Do you happen to have a part number for the brass one you suggest?

Thanks.

if you prefer an "impregnated BRONZE" insert you'll just need to ask for one from most vendors. GM # for the original "bushing type" for the LT5 is/was 10125896. Use an impregnated insert "dry" as it comes out of the box. The GM is also "fluted". Jim at PowerTorque I believe still keeps this.

Removal of the old is NOT accomplished using the old grease compression method some are accustomed to doing. If it's a "FOR HIRE" clutch job make sure you mention this ..................

[cadillac531]

if you prefer an "impregnated BRONZE" insert you'll just need to ask for one from most vendors. GM # for the original "bushing type" for the LT5 is/was 10125896. Use an impregnated insert "dry" as it comes out of the box. The GM is also "fluted". Jim at PowerTorque I believe still keeps this.

Removal of the old is NOT accomplished using the old grease compression method some are accustomed to doing. If it's a "FOR HIRE" clutch job make sure you mention this ..................

Thank you for the info. Is there a special way to remove the old one? Slide hammer?

[WVZR-1]

Thank you for the info. Is there a special way to remove the old one? Slide hammer?

Slide hammer/KNOCKER does very well .............

[cadillac531]

Can anyone tell me what causes a pilot bearing to go bad? I can understand a higher mileage car having this issue, but I've only got 33k miles on it. Can these go bad from lack of use?

[Demps]

Not "bad" per say. It is solid (unless roller type). The noise is most likely from it slipping/spinning in back of crank.

I'm out of town but can help in a couple of weeks if needed. I use a harbor freight blind bearing puller to remove it. And an undersized-to-bore socket to reseat. May consider new clutch disk, at a minimum, when changing.
Ted

[XfireZ51]

Thanks for the reply. In a previous post I found, Mark Haibeck suggested this pilot bearing gm pn14061685 saying it won't come loose. Do you happen to have a part number for the brass one you suggest?

Thanks.

Here's one from Jerry's Gaskets.

http://www.jerrysgaskets.com/bushing-transmission-pilot-90-95-8b2/

Apologies. BRONZE not brass. Thanks WV!

[cadillac531]

Not "bad" per say. It is solid (unless roller type). The noise is most likely from it slipping/spinning in back of crank.

I'm out of town but can help in a couple of weeks if needed. I use a harbor freight blind bearing puller to remove it. And an undersized-to-bore socket to reseat. May consider new clutch disk, at a minimum, when changing.
Ted

It is stock from the factory. Did they come only with the solid one? Also should I be concerned with damage to the crank?

Thanks.

[Demps]

It is stock from the factory. Did they come only with the solid one? Also should I be concerned with damage to the crank?

Thanks.

Yes (I think).

No. I haven't heard of or seen damage and as short of a time as you've experienced it I wouldn't think so.

Ted