Be Aware: Junk Clutch Pilot Bushings!!!
 

Hi everyone. I just wanted to put up a post to hopefully save some of you four-speed guys some time and grief in the future.

Last winter, I had my 1965 GTO 389 engine freshened. I also had the Muncie transmission looked at, because everything was apart anyway. I decided that because the engine and transmission were separated, I might as well go ahead and put in a new clutch.

I ordered a clutch kit locally and bought a new pilot bushing (paid $5.00) through a Pontiac mail order company. The company name is not important, because I am not writing this to trash the company. I am writing this to help you know what to look for in a pilot bushing. It really does matter.

After assembling the engine and transmission and putting a few miles on, I noticed a screeching/squealing noise from the transmission area. This noise would only occur with the clutch pedal pressed to the floor, which means the input shaft is stationary and not turning at engine speed.

I did some Googling about my situation, and found several sites with information about junk pilot bushings. It seems these Chinese made units are magnetic, which means they have a high iron content. It is this iron content that not only makes the squealing noise, but can wipe out your input shaft over time.

I was directed to a company out of New York called Autogear, who specializes in driveline stuff. I spoke to a gentleman by the name of Nathan who indicated that he had several custom Oilite bushings in stock but none for a Pontiac. But he was willing to make one.

I ordered another cheap $5.00 pilot bushing and had it sent directly to Autogear. They have now created a Pontiac bushing that is available in stock. It is true Oilite, not the magnetic junk that I originally bought.

My buddy and I pulled my Muncie yesterday and installed the new Oilite bushing. And sure as hell, the pilot bushing we removed stuck to my magnet like glue. In fact, my buddy shook the hell out of the magnet and could not shake the bushing off of it. It was ridiculous.

Anyway, this is not a commercial for Autogear, nor am I affiliated in any way with them. In fact, I just found another true Oilite bushing available at the McLeod Clutches web site.

The moral to this story: wherever you buy your pilot bushing, BE SURE it is not magnetic. The magnetic ones sell for about $5.00, while the proper Oilite bushings are in the $35 to $40 range. Oilite is oil-impregnated, and that is what saves your input shaft.

Whatever you do, spend the big money for the proper bushing. Saving thirty bucks or so to find out later that you have a steel bushing riding on your input shaft is not a good deal.

You can use a bushing if you want, and some people prefer to, but Pontiac used the 7109 ball bearing in every manual trans V8 application. Trouble is the 7109 bearing is not commonly used in industry anymore, so it is rather expensive. Some people have used the 6202 bearing, but the crank hole may need to be machined a bit deeper.

See: http://www.pontiacpower.org/PontiacCranks.htm

Agree a sintered iron bushing would get noisy once the oil cooks out. At least bronze will remain relatively quiet.

thanx for the heads up. will be tearin into my 76 today. i'll add that to the checklist
Kevin

If it ONLY happens when the clutch is pressed it's most likely the throw out bearing not the pilot bushing

Many people don't recommend a bearing, as they do not tolerate slight misalignment as well as a bronze bushing will. There is also the argument about the "moving parts" in a ball bearing. If one of the moving parts fails, the others quickly follow and you have a mess on your hands.

From the research I have done, I feel better with a bushing than I would with a bearing. Your mileage may vary.

Noise
 

I agree with what you are saying in principle, and your idea is what is normally the issue. However, in this case, it was a bad pilot bushing without question. The throw out bearing is pristine.

When you step on the clutch, the throw out bearing contacts the "fingers" of the pressure plate. But don't forget that while this is going on, the transmission input shaft ceases to turn. So, now you have a stationary input shaft while the crankshaft remains at engine speed. Because the pilot bushing is "part" of the crankshaft, the pilot bushing is spinning on a stationary input shaft. This is precisely the source of my noise. Steel on steel.

When you let off the clutch pedal, the input shaft spins in conjunction with the pilot bushing, so my noise would go away.

What did you use for lube on the bushing?


Using High temp Wheel bearing grease eliminates issues.

Curious......... How can you get screeching if there is grease in the bushing?
The iron percentage content is to keep the bushing from wearing and keep the hole centered.

It's not the Chinese made units as I have pilot bushings in stock that are over 20 years old and have a magnetic content from Pioneer.

No Lube
 

Hi there. To be dead honest, I did not use any lube whatsoever on the original Chinese bushing because true Oilite is not supposed to be lubed. As this was my first time ever doing a project like this, I did not realize that this Chinese bushing was not true Oilite, so I installed it lube-free and went to town.

If I had of known about the high iron content in the first place, I would have either (A) lubed it with high temperature wheel bearing grease like you suggest, or (B) thrown it in the garbage and bought a true Oilite bushing.

As it stands at this point, I chose option "B". And I did not put any lube on the bushing once again, because this time it is a true Oilite bushing, complete with vacuum-impregnated lubricant.

I called Beemer Precision, the makers of true Oilite Bronze, and they assured me that if in fact my new bushing is genuine Oilite (which my new bushing definitely is), that no additional lubricant is necessary. As the bushing begins to warm up, it slowly releases its factory-installed lubricant.

I actually purchased an extra true Oilite bushing from Autogear just to have on the shelf. It is amazing to see the "film" of lubricant through the zip-lock bag it is stored in. The bag looks quite cloudy.

Conversely, I kept my original offending Chinese bushing and also put it into a zip-lock bag. There is absolutely no sign of a lubricant whatsoever.

So, as I have now learned, I guess you could get away with some wheel bearing grease on a high-iron (magnetic) bushing, or go the true Oilite route.

Knowing that the true Oilite offering is permanently lubricated and is "softer" on the transmission input shaft, I would definitely stick with the Oilite bushing.

Having used the std Pilot bushing since the 60's with lube (owned a lot of 4 spd cars and a 68 Z-28) & (As per industry install instructions) and NO issues I wouldn't say Chinese as I don't think they were made back then in China.

All pilot bushing are metallic with ALL manufactures, I.E. Chevy, Ford, Mopar, the list goes on. So don't blame the product, it's knowing what you are supposed to do if you are going to do it yourself. Hope the new pilot bushing has the right hardness to handle the loads of the input shaft.

Millions were and are sold.
As you stated, you didn't lube it.

Question: So if oil weeps out the Oilite brg, when does it reach it's saturation point and no more oil is impregnated in the bushing?

Not doggin ya dude, but having sold and used aftermarket pilot bushings for over 45 years I knew there had to be obvious reason.

Have fun with you ride and hope it works out for ya.

No offence taken. I do not think you are doggin' me at all. In hindsight, you are correct in the fact that I should have lubed the magnetic bushing but I did not know that because I assumed it was self-lubricating (Oilite), which of course it wasn't. So, in essence, I feel that my squealing could have been eliminated by applying proper grease to the improper material.

My personal opinion still remains: for those of you out there that have the experience to know that these magnetic bushings need lubrication, I guess they will work. But I believe there is a better way (the true Oilite bushing).

Just so you know where some of my research comes from, I have supplied a few links:

http://forums.corvetteforum.com/c1-a...-question.html

http://www.camaros.net/forums/archiv.../t-150426.html

http://www.chevelles.com/forums/arch.../t-357685.html

I just don't want to see anyone in the situation I found myself in, but at least this thread will help people realize there are actually two very different types of bushings available:

1: Iron-containing magnetic bushings that must be lubricated.
2: True Oilite bushings that are plug and play.

they did not. do a search.

That is what I thought...
 

That is what I thought, and every old "NOS" GM pilot bushing I have ever seen "appears" to be genuine Oilite Bronze. I say appears because I have never actually had one in my hand.

Give me a few minutes, and I will be back. I am going to take a picture of the junk steel bushing I took out of my car side by side with a true Oilite bronze bushing (my spare).

I think you will be able to see stark colour differences...but you be the judge in a moment or so.

OK. I have snapped a total of five pictures, and would like to take a moment to explain each.

Photo one shows a picture of a genuine Muncie transmission input shaft. A transmission guy gave this to me to use to install the new pilot bushing as well as to use this as a clutch disc installation tool. If this input shaft looks a little weird to you, it is. A machinist friend of mine cut the gear off at the end of the shaft for me. He made it easier for me to use as the aforementioned clutch disc installation tool. This genuine Muncie input shaft fit much better than the cheap plastic installation tool supplied with the clutch kit, enabling the transmission to slide in much smoother. Note the diameter of the shaft. The Chinese magnetic pilot bushing is on the bottom, and the new Autogear Oilite pilot bushing is on the top. The Chinese bushing had been used for about 1000 squealing miles before I took it out. It was cleaned up with brake clean before this photo.

Photo two shows the magnetic Chinese bushing taken out of the car. Note the .6035 measurement. I do not know what diameter this bushing left China with, but it is a lot bigger diameter now than the genuine Muncie input shaft would like to see. However, as PONTIAC DUDE suggests, I obviously should have lubricated this bushing. The extra big diameter was probably caused by lack of lubrication, hence the squealing.

Photo three is pretty straightforward. This picture shows a new Autogear Oilite bushing. It is virgin. Note the measurement of .591.

Photo four shows the Autogear Oilite bushing on top, and the Chinese magnetic bushing on the bottom. Again, the Chinese bushing has been well cleaned. Just showing this picture for comparative purposes, but note the Chinese effort looks far from bronze.

Photo five supports all the information from the links I supplied above in an earlier post. I put the bushings side-by-side on the counter, then "snuck-up" to them with a magnet. I don't need to tell you which one stuck and which one is laying on the counter.

At the end of the day, I fully realize that PONTIAC DUDE is correct in saying that I should have lubricated the magnetic bushing. It certainly would have eliminated the squeal and excessive wear. Yet, all my research pointed to not having to lubricate the bushing, because I believed it to be self-lubricating. It wasn't, as the calipers show. I also believe this: PONTIAC DUDE has been lubricating pilot bushings for over 40 years. Somewhere, in the span of 40 years until now, the composition (metallurgy) of these bushings has gradually changed. Forty years ago, I believe they were genuine Oilite and that fact that PONTIAC DUDE added extra lubrication really did no harm. As the metallurgy changed, PONTIAC DUDE continued his method of lubricating them and had no problems because the more modern bushing actually requires lubricant. If I am correct, PONTIAC DUDE may have spared tons of more modern pilot bushings because of his original methods, and there is certainly nothing wrong with that!

I would absolutely love to get my hands on a genuine NOS GM pilot bushing just to see what material they were made of back then. I would bet the farm that they were Oilite or a derivative of the same.

Please enlighten me. If I get a chance I'll look in my parts books over the next few days.

FWIW...Pontiac used a bearing from the factory in the (70,71,72) A-Bodies that I've owned.

I have run a stick in all my Pontiacs for over 30 years for thousands of miles. One street combo at over 600 hp/TQ in a 3600 lb GTO power shifted on drag radials. Never a failure from the bearing. Currently run over 800 hp in my GTO running a Timken bearing (none better). When people tell you not to run the bearing because they will fail, ask them if they also swap out their wheel bearings for a bushing.

The tolerances need to be tight and when the bellhousing is properly indexed to the block the trans will go on and off smoothly and the parts will last.

Order the Timken 7109 clutch pilot bearing from Summit Racing for $24.97, check the bellhousing alignment, check to see the inputshaft spins true and be done with it.

Good luck.

Do.......A.......Search......

Have always used bearings, not bushings. For the past 35 years and a ton of miles, never a single problem. If the trans/bellhousing does not line up properly, it needs to be fixed. JMHO. Use a bearing and be done with it, as stated previously.

Not the same...
 

With all due respect, I am not too sure about this particular analogy. You are talking about a wheel bearing that bears the constant weight of the car while simultaneously being subject to braking and cornering forces. They also have to contend with heat from the brakes.

A pilot bearing/bushing does not even come close to that type of environment. As stated earlier in this thread, the pilot bearing/bushing only comes into play when the clutch pedal is stepped on. It really only supports the input shaft, not the weight of an entire vehicle. In my opinion, the pilot bearing/bushing has a very "part-time job" compared to a wheel bearing.

Perhaps I should have gone with a roller bearing as both my 1965 and 1968 Pontiac Service Manuals definitely discuss a bearing, and I just noticed this fact last night. My bad. However, I just heard (and read) about so many horror stories with a bearing, that I decided to go the Oilite bushing route.

Had I gone with a bearing, I definitely agree that Timken is about as good as it gets. In other applications, mostly powersports, NTN is another great choice.

I will certainly be honest and post in the future should I have a problem with the Oilite bushing. I feel forums like this only benefit from honest feedback, and I have certainly gained a ton of knowledge on this board. Thanks for that.

Exactly...so why the concern that a pilot bearing will fail.

Regardless, to each his own. Good luck and have fun banging the gears. It is always good to hear of someone running a three pedal car.

Dan

I did an internet search and did not find a list of Pontiac V8 engines that used a pilot bushing from the factory. Sure people make them and sell them and some people prefer them over a bearing, but AFAIK the factory put 7109 bearings in them.

Here is an excerpt from the 1974 parts book that only shows a pilot bearing for V8s:

I always preferred the bearing over a bushing until the bearing in my 428 seized and chewed up the input shaft, then spun in the crank. Ruined the hole in the crank, and chewed up the input shaft of my tranny. Started thinking the bushing wasn't such a bad idea after that. I suppose a bearing seizure is quite rare though, and I will probably chance one again in my 64 GTO. My bearing seizure was back in the mid 80's before the Chinese stuff started coming over, so it wasn't from that.

That is the message I continue to find in my research on this topic. I share your thinking in that roller bearing seizure is likely pretty rare, especially with a product like Timken. If a roller bearing does fail, however, it can get ugly.

On the other hand, if an Oilite bronze bushing fails, it is not hard enough to bugger up anything.

We will see how this whole thing works out, I guess. If the Oilite bronze bushing doesn't work out, it will be off to a 7109 Timken bearing for me.

exactly, if the tranny or the bell housing dont line up.....

then, if you did a search you would note that there are other possible ways the bearing can and will fail if its not manufactured properly or installed improperly and when it failes it takes out a lot of other much more expensive parts too so unless your footing the bill ....

really a bushing is fool proof and virtually indistructable pretty much reusable too

so...

do a search....on this forum....

then if you have many hours to waste and thousands of dollars to risk then roll that dice

and remember, there are many failure modes unrelated to manufacture quality .

what did Shakespeare say?.... Betwix cup and lip lies many a slip.....

I have always used the Dorman bushing with no issues.

http://www.dormanproducts.com/p-18309-690-023.aspx

Hindsight now says I will lube the next one a bit.

Ram AIR, I'll keep on rolling the dice. The current input bearing has been working in my '65 since 1984.....I guess it would have failed by now. Back then, parts were made in the USA. I'm not worried a bit.

Had a bearing come apart on me last fall during a 1/4 mile launch. Just the plastic shield part broke up. Those plastic pieces took out my clutch and flywheel. Had a spare flywheel but a new clutch and disc cost me over 500 bucks not to mention all the work involved. Just installed a bushing after soaking it in that friction reducer stuff Big Daddy Don Garlits sells. probably soaked for a few months since I could never find time to install it. have a cryoed and polished input shaft by liberty transmission so hopefully will do the trick. Bellhousing was aligned according to Browell alignment tool. Those things are really easy to use by the way.

Pilot Bearing vs. Bushing
 

Wow. Sorry to hear of your misfortune. That's no good, for sure.

As I mentioned in a previous post in this thread, I did go through some work and effort to have a custom Oilite bushing made up. The main reason I did this is because I thought that these cars originally came from the factory with a bushing. Why? Well, the vendor I bought the steel (magnetic) bushing from only offered a bushing (but not a bearing) in their catalogue. Being a true newbie to four-speed stuff, I didn't know that bearings were even available for this application. After installing and hearing the squealing produced by this steel bushing, I immediately Googled the issue and came upon piles of information on these undesirable steel bushings. So my next move was to track down a proper Oilite bushing, and I finally got one in my hands. But I still did not yet know that these cars actually left the factory with a bearing!

It was not until I consulted both my 1965 and 1968 shop manuals that I realized these cars came from the factory with a bearing. Which leads me to wonder now:

The research I did uncovered many people that don't like the bearings because of possible bell housing misalignment. They say if you are ever to use a bearing, you must make sure that your bell housing alignment is spot on. And this makes nothing but sense to me.

BUT...How many of these cars over the years were driven into Joe's Transmission for a clutch replacement, which likely would have included replacement of the pilot bearing? My bet is that Joe's Transmission not once checked bell housing alignment. Ever. They would have removed the old pilot bearing, installed a new one, replaced the clutch, and told the customer to have a nice day. Yet somehow, these bearings survived. My guess is that GM must have had pretty darn good alignment from the factory, seeing that these cars left the factory with a bearing.

Anyway, here I now sit with a brand new Oilite pilot bushing in my car. I can't yet give a report on its performance, as we have sixteen-thousand feet of snow here and the car is resting in the garage until at least May.

But I do know three things, and I hope it saves someone some hassle or helps them with their choice down the road.

1. There exists steel (magnetic) pilot bushings out there in the marketplace. If you choose to go this route, be sure to lube the bushing to avoid metal-to-metal contact. These magnetic bushings sell for about $5.00 or so.

2. You can buy an Oilite pilot bushing from places like Autogear or McLeod Clutches. No lube is necessary, and the bushing is softer than the input shaft of the transmission. These Oilite bushings cost about $40.00 or so.

3. You can do what the factory did, and use a roller bearing. You can install it as-is and take your chances, or check and correct any bell housing misalignment issues.

In hindsight, I think any of the above solutions will work.

Jeez. For the amount of time and research I have done on this topic, I could have done a frame-off!;)

Great thread.
I have a question.

Does anyone know if the Dorman input shaft bearing comes in a roller type (not bronze) and did Dorman also sell it as a National #7109 part?

Are these the same part or would Dorman have a different part#?

This is the link to what I ordered off of ebay .
Upon opening the package, its actually a National #7109 bearing made in China. http://www.ebay.com/itm/261314051999...382016&vxp=mtr
I could've picked this up at the local parts store.


Don

Timken
 

You probably could have got it at the parts store, or even a local bearing/power transmission outlet.

If I went the roller bearing route I would feel better with a Timken (USA) or an NTN (Japan). We have had tremendous luck with both brands in high demand circle track and snowmobile racing applications. I have since looked up this bearing (7109) in an NTN and it doesn't look like it is available. But I did find this:

http://www.summitracing.com/parts/tmk-7109

Hope this helps!

When I changed over from an auto I tried to install the bearing and it was to sloppy but the bushing fit perfect I really didnt understand why but it went that way.

Another thing: I've always used a bearing, as I stated, but it's been a long time since I put a clutch in one of these cars. The last one was 20 years ago with a friend's car. The pilot bearings had NO PLASTIC anywhere on or in them. The one that's been in my '65 for the past 30 years is a Timken, and it's a ball bearing, not a roller bearing. And yes, I always lube these on install with hi-temp synthetic wheel bearing grease. Being a ball type bearing, the inner race has the ability to tilt a bit if the trans/bellhousing alignment is not perfect. A roller bearing won't allow this. Plastic pilot bearings? You have got to be kidding.

He's talking about the plastic dust covers that come on sealed bearings. The bearing itself is not plastic.

Dust Seals
 

I agree. They are a removable type dust cover. They can be removed with a pick or similar tool if desired. Many snowmobile guys around here pick the seals out of their bogey wheels, clean the roller bearing in solvent, repack it with grease, and reinstall the dust seals.

In this case, of course, they are more like "snow seals".

But you get the picture.

4 my 5sp install
 

Seen this and it's my preference as well as I do my 65.Do have a couple of questions about the 7109 though. First is the bearing correct for my Tremec 5sp i'll be using (maybe I need to mic the input shaft!) and also I see what appears to be a retaining clip or lip on the bearing.Does the bearing not mount flush?

Gotcha. The bearings I've used had no dust seal and were open on the crankshaft side. I've always packed the open side with grease. Nowhere for dust/dirt to get in once it is installed.

No.... Got You!

do a search here on this site and you will see that these bearings come with no seal on either side, a seal on one side and a seal on both sides.

also.....that same search will show that the seal can be of metal, plastic or a composite material called micarta (?)

Oh and in addition to god knows what the chinese are selling, there is two types of bearing type bushing, (a ball and a roller type) a lubricated bronze bushing and currently a composite plastic bushing.

all this information is here on this site if you do a search.

you may or may not have any concern about the grease you pack in the bearing unless you lucky enough that it only seaps out with centrifugal force and ruins your clutch and disc. its not about dust/dirt getting in... its about the grease getting out. why cant people get that?

if it were to actually fail, it would do a lot more(read expensive) damage than that. don't fight it, do a search

Ram Air, respectfully, I have never had an issue. In decades. I pack a small amount of grease in the open side of the bearing, and that open side gets installed into the crankshaft. The input shaft of the trans then gets installed inside the inner race of the bearing. There is no place for the grease to go. There is no way it can get out and past the input shaft. Centrifugal force would simply throw any excess on the inside of the crank flange, but I haven't had even this happen, as I use a very small amount of grease. I probably put more grease on the input shaft splines to help out the clutch plate. The "Gotcha" was referring to me not knowing about the plastic covers on the newer bearings. That I got the point. It had nothing to do with one-upmanship.

How much grease do you use on a bushing? Do you fill behind it or just a little bit?

fair enough, you are one person who has had good luck and no failure with grease and failed bearings. but others replying to this thread and other threads on this forum can tell of major and expensive problems resulting from a failed bearing.

you are correct that a small amount or grease will be slung out when its put on the imput shaft befor installing the tranny. a little goes a long way

but I have seen where it will seap past the outer race of the bearing between the bearing and the crank. in most time but not all times its from over geasing the bearing itself or from leaving grease in the crank shaft after removing the bearing... or the bushing for that matter.

no its got nothing to do with one up manship on this side either. just trying to put good info out there and reffering to other information already on this forum where this has been hashed to death. the final choice is ours alone to make but its important to appreciate all the facts on both sides.

I guess I mis understood what you meant when you said gotcha when you stated that the bearing you installed had no seal and were open on the crankshaft side, actually it would be open on both sides if it had no seal and it would not matter which side is the crank side, and you really do want at least the fly wheel side to be sealed or you will have a problem with grease being slung out. No one up manship here, just hoping that readers understand that its important when installing a geased bearing that there can be a lot of misinformation and confusion out there.

Me? I always use a bushing and re use a bushing and never had another failure

Well stated. To clarify, the bearings I have installed were closed on one side and open on the other side. Sheet metal cover. So I installed the open side towards the crank. But the last one of these bearings I installed was in 1994 in a friend's car, and it's still ok, too. I use so little grease that there is virtually none in the pocket of the crankshaft at all. Just enough to barely pack the bearing. Have also used oilite bushings in customer cars with no issues, either.

another issue not entirely relevant to us here but if moisture gets in the rollers, and more specificly water or mud, it will do a roller in in like half an hour, I seen that happen in mud bogging. not relevant to most of us but hey who knows

Grease
 

This is a good question. On a genuine Oilite bushing, you don't need any grease at all. On the magnetic "steel" bushing, you certainly need grease, as I found out when I didn't grease it and it squealed like a pig.

If you happen to go the steel bushing route instead of the genuine Oilite, (I wouldn't, grease or no grease) I would apply a reasonable amount of grease but not so much that it would fling off.

This is why I like the genuine Oilite bushing idea so much. There is no risk of grease contamination whatsoever, and the bronze is softer than the transmission input shaft.

As I have said in a previous post, knowing what I know today, I would go Oilite or a ball bearing. Oilite is pre-lubed and gentle on the input shaft, while a ball bearing was OEM.

Sorry for the delay in responding, I don't look at the street forum often.

From my experience on OEM cast and Scat forged cranks the Timken 7109 is flush when installed. The photo on the Summit Racing site is a representation, not the actual part.

I am not familiar with the Tremec, I can only speak to what I have run...Muncie, Autogear and GForce transmissions. The inner diameter of the 7109 is 0.59 in. As you said, put a mike on your input shaft and verify it.

Curious...does Tremec spec a bushing or bearing?

Good luck...keep banging those gears.

i wonder
 

Thanks for the response Dan and now that you mentioned it,i don't know....but will find out if bearing or bushing is spec.Good point as I may have otherwise overlooked that !

A Verdict?
 

Well, here is the verdict so far. I have driven the car exactly 300 miles now this spring, and the genuine Oilite pilot bushing has been perfect thus far. I realize time will tell, but I have not yet heard even a hint of squealing. Conversely, last spring the magnetic bushing squealed right away.

We will see what happens as the summer progresses...

Un-equal pressure to the pressure plate fingers might cause the same noise but I'm just speculating.

There is nothing wrong with the bronze type bushings supplies by Pioneer and such. When you do not install it properly and dry you get the results you got. It's a fact that the bushings need grease to work properly. Metal on metal without some form of lubrication ends up with bad results. I have used the std bushings for over 50 years and NO issues.
But glad the Oilite bushing works for ya.

He admitted after I asked that he put the bushing in dry thus creating the issue to begin with.

My 81 Trans Am has made the same noise he's talking about a couple times, there was also a pulsation in the clutch pedal when it happened.