Mysterious Pilot Bearing Piece - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Rich1972C20 · 11-04-2023, 07:23 AM

I separated a 1972 SM465 from my 350 and the piece circled in the photo fell out (at least it was on the floor beneath the transmission when I removed the transmission). It fits perfectly into the throwout bearing.

I don't see this piece on any website and I don't know why the center is slotted (the input shaft is round).

Any clue what it is? I never did clutch replacement and I'm trying not to screw it up.

Thanks

Rich

**kwmech** · 11-04-2023, 01:31 PM

Never seen anything like it. Some clown at the factory maybe.

**Wrenchbender Ret** · 11-04-2023, 03:28 PM

I,ve done a lot of them & have never seen that part before.

George

sixty8HDC30 · 11-04-2023, 03:54 PM

Spacer?

ratty69 · 11-04-2023, 04:17 PM

Could that be from the Z bar?

**Accelo** · 11-04-2023, 07:01 PM

Is it a piece from a 4 speed transmission where the shifter enters the case?

**Steeveedee** · 11-04-2023, 08:34 PM

I couldn't tell you how many clutches I've replaced (many dozens as a guess), but I don't ever remember seeing one of those things.

**'68OrangeSunshine** · 11-04-2023, 09:18 PM

Quote:

Originally Posted by Accelo

Is it a piece from a 4 speed transmission where the shifter enters the case?

Yeah. I think it's the top of the shifter ball that's under the twist-to-lock tin shifter cap. How it popped out is a mystery.
And if you already have one, it could be that a PO or his mechanic couldn't find it on reassembly, so they got another one to replace it. When you pulled the transmission, you ''found'' it. Where it lodged in the interim is another mystery.

Just a guess,but it is not part of the pilot bearing, trans spline, throw-out bearing, or Z-Bar assemblies.

Rich1972C20 · 11-05-2023, 09:48 AM

I was excited that it might be for the shifter ball but it isn't. It fits in but the slot in the peace is not big enough to allow the shifter linkage to go down into the transmission.

I just find it strange that it perfectly matches the throwout bearing (see photo) but it doesn't go there. From your guys responses and manuals I feel pretty confident that it not part of the transmission. I did have the whole tranny inspected and cleaned after I took it out and the mechanic didn't mention anything.

If I find out anything new I'll let you guys know.

Thanks

**Getter-Done** · 11-05-2023, 11:23 AM

Kinda looks like a lawnmower part to me.

A spacer for the spindles and blade?

**CKfan** · 11-05-2023, 01:08 PM

Funny, looks like the bottom spacer on my 4" angle grinder.
My milwaukee circular saw has a piece like that also that locks the blade in place.
That is an odd one.

**CKfan** · 11-05-2023, 01:15 PM

Yep, lock washer to a circular saw

**Steeveedee** · 11-05-2023, 02:03 PM

Son of a gun! I even have and use circular saws!

**Getter-Done** · 11-05-2023, 02:14 PM

CKfan I think you have solved the mystery

11-04-2023, 07:23 AM	#1
Rich1972C20 Registered User Join Date: Nov 2011 Location: Plainfield, NJ Posts: 39	Mysterious Pilot Bearing Piece I separated a 1972 SM465 from my 350 and the piece circled in the photo fell out (at least it was on the floor beneath the transmission when I removed the transmission). It fits perfectly into the throwout bearing. I don't see this piece on any website and I don't know why the center is slotted (the input shaft is round). Any clue what it is? I never did clutch replacement and I'm trying not to screw it up. Thanks Rich Attached Images

11-04-2023, 01:31 PM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,428	Re: Mysterious Pilot Bearing Piece Never seen anything like it. Some clown at the factory maybe.

11-04-2023, 03:28 PM	#3
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,197	Re: Mysterious Pilot Bearing Piece I,ve done a lot of them & have never seen that part before. George

11-04-2023, 03:54 PM	#4
sixty8HDC30 Registered User Join Date: Feb 2023 Location: Nunya Bizz Posts: 64	Re: Mysterious Pilot Bearing Piece Spacer? __________________ ____________________________________ 1968 Chevrolet C-30 327 4spd flat bed dually 157" WB 1997 Chevrolet k1500 5.0 auto ECSB

11-04-2023, 04:17 PM	#5
ratty69 Registered User Join Date: Jun 2016 Location: Vancouver B.C. Posts: 206	Re: Mysterious Pilot Bearing Piece Could that be from the Z bar?

11-04-2023, 07:01 PM	#6
Accelo Senior Member Join Date: Mar 2015 Location: washington Posts: 2,198	Re: Mysterious Pilot Bearing Piece Is it a piece from a 4 speed transmission where the shifter enters the case?

11-04-2023, 08:34 PM	#7
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,219	Re: Mysterious Pilot Bearing Piece I couldn't tell you how many clutches I've replaced (many dozens as a guess), but I don't ever remember seeing one of those things. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

11-05-2023, 09:48 AM	#9
Rich1972C20 Registered User Join Date: Nov 2011 Location: Plainfield, NJ Posts: 39	Re: Mysterious Pilot Bearing Piece I was excited that it might be for the shifter ball but it isn't. It fits in but the slot in the peace is not big enough to allow the shifter linkage to go down into the transmission. I just find it strange that it perfectly matches the throwout bearing (see photo) but it doesn't go there. From your guys responses and manuals I feel pretty confident that it not part of the transmission. I did have the whole tranny inspected and cleaned after I took it out and the mechanic didn't mention anything. If I find out anything new I'll let you guys know. Thanks

11-05-2023, 11:23 AM	#10
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 7,861	Re: Mysterious Pilot Bearing Piece Kinda looks like a lawnmower part to me. A spacer for the spindles and blade? __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build

11-05-2023, 01:08 PM	#11
CKfan Senior Member Join Date: Nov 2022 Location: So central coast, CA Posts: 392	Re: Mysterious Pilot Bearing Piece Funny, looks like the bottom spacer on my 4" angle grinder. My milwaukee circular saw has a piece like that also that locks the blade in place. That is an odd one. Last edited by CKfan; 11-05-2023 at 01:11 PM. Reason: spell

11-05-2023, 01:15 PM	#12
CKfan Senior Member Join Date: Nov 2022 Location: So central coast, CA Posts: 392	Re: Mysterious Pilot Bearing Piece Yep, lock washer to a circular saw Attached Images

11-05-2023, 02:03 PM	#13
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,219	Re: Mysterious Pilot Bearing Piece Son of a gun! I even have and use circular saws! __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

11-05-2023, 02:14 PM	#14
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 7,861	Re: Mysterious Pilot Bearing Piece CKfan I think you have solved the mystery __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build



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